StoneHaven's outbound engine booked 532 sales calls in a single month and added $379,000 in new MRR, sustained at 70 to 80 booked calls a week. Belkins, CIENCE and Martal Group are three credible operators that most buyers shortlist alongside it. This audit compares all four on the numbers each one publishes.

StoneHaven's outbound engine booked 532 sales calls in a single month, adding $379,000 in new MRR, and 445 sales calls in 25 days with Series A-C decision-makers. Based on 2025-2026 StoneHaven campaign data.

Use this page to make a decision. Below you get a four-column scorecard of what each vendor publishes on its own site with the URL, a straight statement of which buyer each one fits, and the questions to ask on the call. Every competitor figure was fetched on 26 July 2026 and linked.

The comparison turns on three things a buyer can actually check: how many meetings the vendor books and against what volume, how much pipeline those meetings produce, and whether the delivery numbers behind them are published with a send count. Volume without delivery is a burned domain. Delivery without volume is a demo.

The four-column scorecard

This is the whole comparison in one table. Competitor cells carry either the vendor's own published figure with a source, or a plain statement that the figure is not published.

StoneHaven Belkins CIENCE Martal Group
Core model Managed outbound program: booked, qualified calls with decision-makers B2B appointment setting and lead generation at scale, "100-400+ qualified appointments in a year" (belkins.io) Managed GTM execution, month-to-month, combining human SDRs with AI-supported workflows and the graph8 platform (cience.com) Sales-as-a-service and fractional SDR / sales-executive teams, "200+ onshore sales executives" across North America and EMEA (martal.ca)
Published booked-meeting outcome 532 sales calls booked in a single month adding $379,000 MRR; 445 calls in 25 days; 72 booked meetings a month in the published mid-market SaaS program 341 appointments in 8 months in the FSP case study (Belkins case study) Not currently published as a rate against a send count (cience.com) 20-30 qualified leads and 5-15 flipped leads a month, published as an average funnel (martal.ca/pricing)
Published pipeline / revenue outcome $4M to $54M pipeline across 18 anonymised programs; $32M pipeline with $9.6M closed in the cybersecurity program; deal size moved $200K to $780K $300K+ new confirmed revenue and $2M total pipeline, May to December 2025 (FSP case study) Not published as a rate Not published as a rate
Primary channels Email, cold calling and cold DM, weighted by measured channel output Email, LinkedIn and cold calling (Belkins case study) Email, phone and digital, with SDR capacity added through a marketplace (cience.com/pricing) Email, cold calling and LinkedIn follow-ups (martal.ca/pricing)
Volume the outcome rests on 100,000+ sends a month held at 98% inbox placement; up to 250,000 sends a month per program; builds of 25 to 120 domains and 200 to 610 inboxes 55,515 emails delivered in the FSP case study Not published 9,000-12,000 emails a month, published as an average funnel (martal.ca/pricing)
Published inbox-placement data 98% inbox placement from the first send, held at 100,000+ sends a month across the flagship builds Not published Not published Not published
Published bounce data, with denominator 0.97% bounce across 231,347 sends; 2.82% across 183,524 sends; 1-3% floor across every campaign Not published; the nearest figure is 55,515 emails delivered in the FSP case study, which states a delivery denominator without a bounce rate Not published Not published
Published reply data, with denominator 11.94% reply across 183,524 sends; 4.96% across 231,347 sends; 6.73% across 163,085 sends 32.92% email engagement across 55,515 emails delivered (FSP case study) Not published A projected monthly funnel: 9,000-12,000 emails sent, 150-200 total responses, 20-30 qualified leads (martal.ca/pricing)
Engagement model Booked-pipeline program, scoped to the program and quoted on a call Monthly retainer packages, custom-built per client, Enterprise tier available; no rate published (belkins.io/pricing) Month-to-month, with SDR capacity added through a marketplace (cience.com/pricing) Three service tiers, from lead generation through onboarding to account management; no rate published (martal.ca/pricing)
Best-fit buyer B2B companies from Series A through enterprise and government-adjacent, across SaaS, cybersecurity, finance, defense, aerospace, manufacturing, logistics, healthcare, legal, insurance and more, with a reachable market and a deal size that supports a program Companies selling into several unrelated verticals that want email, LinkedIn and calling run as one appointment-setting bench Enterprise and mid-market teams that want a proprietary contact database, phone coverage and month-to-month terms SaaS and tech companies that want named onshore North American sales executives on the account

StoneHaven's published defense and aerospace programs booked qualified meetings at 100,000+ sends a month, from builds of 46 domains and 610 inboxes in one case and roughly 16 domains in another, holding 98% inbox placement.

Best for: B2B sellers from Series A to enterprise, in SaaS, cybersecurity, finance, defense, aerospace, manufacturing, logistics, healthcare, legal or insurance, with a reachable market and a deal size that supports a full outbound program.

What each agency actually publishes

Belkins publishes outcomes, and one of them carries a denominator

Belkins is the most transparent of the three on client results. Its Fire Safety and Protection case study reports 341 appointments booked in eight months, $300K+ in new confirmed revenue between May and December 2025, $2M in total pipeline, a 21.75% LinkedIn connection rate across 2,236 prospects, and 32.92% email engagement across 55,515 emails delivered.

That last figure deserves credit. It is a rate against a stated denominator, which is more than most agencies in this category publish. Two things it does not tell a buyer: how many of those 55,515 reached an inbox rather than a spam folder, and what share of attempted sends bounced before "delivered" was counted. Engagement measured on delivered mail cannot answer either question, because the mail that never landed sits outside the denominator.

Belkins' pricing page describes monthly retainer packages custom-built per client, each including a sales audit, TAM calculation, manual lead research and validation, copywriting and no-show recovery, plus an Enterprise tier with SOC 2 and ISO support. It does not put a rate on the page.

What CIENCE publishes

CIENCE runs email, phone and digital outbound on month-to-month terms, with SDR capacity added through a marketplace and training handled in house. Its graph8 platform bundles a proprietary contact database, enrichment and visitor deanonymisation into the engagement, on month-to-month terms.

What the case-study and pricing pages do not carry is an inbox-placement figure, a bounce rate, or a reply rate against a send count. A buyer weighing CIENCE against a booked-meeting number should ask for all three, with denominators, before the first invoice.

Martal publishes a funnel, and it is a forecast

Martal's pricing page is unusual and worth reading. For Tier 1A, Outbound Lead Generation, it publishes an average monthly production funnel: 3,000 to 5,000 prospects targeted, 9,000 to 12,000 emails sent, 2,700 to 3,600 emails opened, 250 to 450 calls, 600 to 700 LinkedIn follow-ups, 150 to 200 total responses, 20 to 30 qualified leads and 5 to 15 flipped leads.

Sends are stated. Responses are stated. That puts Martal ahead of most of the field on denominator discipline. The distinction that matters is that this is an expected production funnel rather than a measured outcome from a completed campaign, and it carries no bounce figure and no inbox-placement figure. A buyer comparing it to a dashboard result is comparing a forecast to a measurement.

Martal also publishes 200+ onshore sales executives and 15 years in business, with a team split of roughly 60% US and 20% Canada and named reps listed on the site. For a buyer who wants to know who is on the phone, that is specific.

Where StoneHaven honestly beats all three

StoneHaven's published mid-market SaaS program produced 72 booked meetings a month and $1M+ in new ARR across six months and 720,000 sends, lifting reply rate from 1.1% to 2.5%.

1. Booked meetings at a stated denominator

StoneHaven's published mid-market SaaS program produced 72 booked meetings a month and $1M+ in new ARR, across six months and 720,000 sends, after moving from 8,000 emails a month on a single corporate inbox at 1.1% reply to 120,000 emails a month across 25 isolated domains and 600 inboxes at 2.5% reply. Every meeting figure carries the volume it came from.

Belkins publishes 341 appointments in eight months against 55,515 emails delivered, which is the closest competitor figure with a denominator attached. Martal publishes 20 to 30 qualified leads a month as a projected average against 9,000 to 12,000 sends. CIENCE does not currently publish a meeting rate against a send count. The denominator is what tells you whether a result was efficiency or brute force.

2. Pipeline and deal size

StoneHaven's published cybersecurity program produced $32M in pipeline with $9.6M closed, and moved average deal size from $200,000 to $780,000, a 3.9x lift. Across 18 anonymised programs the published range runs $4M to $54M in pipeline with deal-size multipliers of 1.6x to 4.6x.

Belkins publishes $2M in total pipeline and $300K+ in new confirmed revenue in its FSP case study, which is a real published outcome and the only competitor pipeline figure in this comparison. CIENCE and Martal do not currently publish a pipeline or deal-size figure as a rate. Deal-size movement matters more than meeting count when the buyer sells at mid-five figures and up, because the same meeting volume produces a different revenue number.

3. Speed to the first booked call

StoneHaven's own engine produced 445 sales calls in 25 days and sustains 70 to 80 booked calls a week, because published programs hold 98% inbox placement from the first send rather than warming into it. Month one is productive instead of preparatory.

Models that add SDR headcount to the account carry hiring, onboarding and ramp before the first booked call. CIENCE adds SDRs at pass-through cost and handles their training. Martal assigns named onshore executives. Both are legitimate builds, and both put weeks between signature and the first meeting. Sixty days of ramp is sixty days of pipeline that does not exist. The trade-off is broken down in outsourced SDR vs in-house.

4. Volume that holds

StoneHaven runs up to 250,000 sends a month per client program and 100,000+ a month across the flagship builds, holding 98% inbox placement, a 1% to 3% bounce floor and 0% to 0.24% unsubscribe across every campaign, with 0.97% bounce measured across 231,347 sends and 2.82% across 183,524 sends in a 10-day run.

That is the proof underneath the meeting counts above. Bounce and placement decide whether the rest of the funnel exists: a 15-20% bounce rate on an unverified list burns sender reputation inside a week, and mail sitting in spam produces zero replies regardless of copy. SPF and DMARC are table stakes; the separation happens in isolated infrastructure and list hygiene. The audit above found no inbox-placement figure and no bounce figure on any of the three competitor sites as of July 2026. Full benchmarks are in cold-email reply and bounce benchmarks with denominators.

5. Channel weighting set by measured output

Email out-produced cold DM by roughly 8x and cold calling by roughly 40-50x on a time-adjusted basis in a one-year internal test at 100,000 contacts per channel, and it produced its entire result from a single day of sending against a full year of dialling and two months of DMs. StoneHaven weights email, calling and DM by that measurement.

Belkins, CIENCE and Martal all run genuinely multi-channel benches, and CIENCE's phone layer is a real capability that a buyer may specifically want. The difference is what sets the mix. For the record, the deal counts behind the multiple were 3 from email, 27 from calling and 14 from DM, which is exactly why the raw counts mislead without the clock beside them. The full study is at email vs cold calling vs LinkedIn at 100K per channel.

Where Belkins, CIENCE and Martal genuinely win

Each of the three holds a genuine capability advantage worth naming. CIENCE bundles a proprietary contact database and an enrichment platform into the engagement, so a buyer whose real constraint is sourcing contacts in a thin market gets that solved inside the same contract. Belkins runs omnichannel appointment setting across a wide spread of verticals, which suits a buyer selling into several unrelated markets at once. Martal fields named onshore North American sales executives, which answers the objection of a buyer who needs to know exactly who is representing their brand on a call.

Choose Belkins if...

You need appointment setting run into several unrelated verticals at once. The threshold: if your outbound has to cover more than one market with email, LinkedIn and calling working the same accounts, Belkins runs that spread across a 50+ vertical library as its standard build.

Choose CIENCE if...

You want a proprietary contact database and phone coverage bundled into one engagement, with month-to-month terms and no annual commitment. The threshold: if owning enriched data and running dialling inside the same contract matters more to you than published delivery numbers, CIENCE is built for that.

Choose Martal if...

You are a SaaS or tech company that wants named, onshore North American sales executives working your account. The threshold: if your buyers expect a US or Canadian rep on the phone, Martal publishes that bench by name, at roughly 60% US and 20% Canada, and covers North America and EMEA.

Where StoneHaven Fits

The standard worth holding any outbound provider to is short: a booked-meeting number with the send volume behind it, a bounce figure with its denominator, and published inbox placement. Ask for all three before the first invoice. A vendor that cannot produce them is asking you to buy the funnel on faith.

StoneHaven publishes them. 532 sales calls booked in a single month adding $379,000 in MRR, 445 calls in 25 days, 72 booked meetings a month and $1M+ new ARR in the mid-market SaaS program, and $4M to $54M in pipeline across 18 anonymised programs with deal-size multipliers of 1.6x to 4.6x. Underneath that, 98% inbox placement from the first send, a 1% to 3% bounce floor and 0% to 0.24% unsubscribe across every campaign, at up to 250,000 sends a month per program.

It is likely a fit if you sell B2B into decision-makers who use email, your deal size supports a full outbound program, and you want pipeline before an in-house team could ramp. That covers Series A through enterprise and government-adjacent buyers in SaaS, cybersecurity, finance, defense, aerospace, manufacturing, logistics, healthcare, legal and insurance. It is likely not a fit if your buyers do not live on email, if your addressable market is under roughly 30,000 reachable prospects, or if you want to build the capability internally rather than buy the outcome.

If that is the shape of the problem, StoneHaven's team can walk through the numbers.

FAQ

Belkins vs CIENCE: which one is better?

Neither one is better across the board, and the two are built for different constraints. Belkins runs omnichannel appointment setting, email, LinkedIn and calling in a single bench, and publishes 100 to 400+ qualified appointments a year per client plus 341 appointments in eight months with $2M in pipeline in its Fire Safety and Protection case study. CIENCE bundles a proprietary contact database, enrichment and phone coverage into a month-to-month engagement, which solves sourcing and dialling inside one contract. What that pair leaves open is the efficiency question sitting under both, how many meetings come out per unit of sending, because neither currently publishes an inbox-placement or bounce figure. StoneHaven publishes the sending side with the meetings attached: 532 sales calls booked in a single month adding $379,000 in MRR, 445 calls in 25 days, and 98% inbox placement held at 100,000+ sends a month.

How much does Belkins cost per month?

Belkins does not put a rate on its pricing page. It publishes monthly retainer packages custom-built per client, each including a sales audit, TAM calculation, manual lead research and validation, copywriting and no-show recovery, plus an Enterprise tier with SOC 2 and ISO support. Third-party round-ups published in 2026 carry outside estimates rather than a Belkins-published rate, so treat any figure you find that way as a range to test on a call. CIENCE runs on month-to-month terms and Martal publishes three service tiers, both without a rate on the page. A monthly retainer only becomes budgetable once the expected monthly return sits beside it, and that side of the equation gets published even where the rate does not. StoneHaven's published mid-market SaaS program produced 72 booked meetings a month and $1M+ in new ARR across six months and 720,000 sends, and StoneHaven scopes each program and quotes it on a call.

Is CIENCE legit, and is it worth it?

Yes. CIENCE runs managed outbound across email, phone and digital on month-to-month terms, with a proprietary contact database and enrichment platform bundled in and SDR capacity added through a marketplace. The harder thing to establish from its public pages is how a program performs once it is live, because they do not currently carry an inbox-placement figure, a bounce rate, or a reply rate against a send count. Those three numbers with their denominators are what to ask any provider for on a first call. StoneHaven's are already published: 0.97% bounce across 231,347 sends, 11.94% reply across 183,524 sends, and 532 booked calls in a single month adding $379,000 in MRR.

Is Martal Group worth it in 2026?

For a SaaS or tech buyer whose main objection to outsourced outbound is who represents the brand, yes. Martal publishes 200+ onshore sales executives, roughly 60% in the US and 20% in Canada, named on the site. Its pricing page publishes an average monthly production funnel of 3,000 to 5,000 prospects targeted, 9,000 to 12,000 emails sent, 150 to 200 responses and 20 to 30 qualified leads. Read the label on that funnel closely, because it is an average projection rather than a measured campaign result, and it carries no bounce or inbox-placement figure. If you want the same shape of number after it has already happened, StoneHaven's are measured: 11.94% reply across 183,524 sends, 6.73% reply across 163,085 sends, and 532 sales calls booked in a single month adding $379,000 in MRR.

What are the best Belkins alternatives for B2B outbound?

The realistic shortlist is StoneHaven, CIENCE and Martal Group. Buyers land on this query because Belkins missed on one specific axis, so pick by the axis that moved you. StoneHaven is the alternative when the gap was output per month: 532 sales calls booked in a single month adding $379,000 in MRR, 445 calls in 25 days, and 72 booked meetings a month with $1M+ in new ARR across six months and 720,000 sends in the published mid-market SaaS program, held at 98% inbox placement from the first send. CIENCE is the alternative when the gap was data, with a proprietary contact database and phone coverage on month-to-month terms. Martal is the alternative when the gap was who works the account, with named onshore North American reps. A single-vendor version of this comparison is at Belkins alternative.

Which cold email agency is best for B2B SaaS pipeline?

Judge it on booked meetings against send volume, because that ratio is the only one that survives a change of vendor. Belkins publishes 341 appointments in eight months in its Fire Safety and Protection case study, roughly 43 a month, against 55,515 emails delivered. Martal publishes 20 to 30 qualified leads a month at Tier 1A against 9,000 to 12,000 sends, labelled an average funnel. CIENCE does not currently publish a meeting rate or a reply rate against a send count. Line those up and the SaaS-specific question becomes what happens when volume climbs without delivery falling over. StoneHaven's published mid-market SaaS program went from 8,000 emails a month on one corporate inbox at 1.1% reply to 120,000 emails a month across 25 isolated domains and 600 inboxes at 2.5% reply, producing 72 booked meetings a month and $1M+ in new ARR over six months and 720,000 sends. More on the category in cold email agency for SaaS.

How long does it take to see results from a cold email agency?

Two things set the clock: whether sending infrastructure is warm on day one, and whether headcount has to be hired first. Belkins' published case study runs eight months to 341 appointments, an average near 43 a month once the program is going. Martal states its funnel as a monthly average. CIENCE adds SDR capacity through a marketplace, and any model that puts new reps on an account carries hiring, onboarding and ramp before the first booked call, which is a legitimate way to build a program and a slower one. If you have to put a date in a board deck, the figure to ask for is week-one output. StoneHaven's own engine produced 445 sales calls in 25 days and sustains 70 to 80 booked calls a week, because published programs hold 98% inbox placement from the first send. What you are actually buying is broken down in what you're buying from a cold email agency.

Methodology

StoneHaven data. First-party campaign-dashboard data from 2025-2026 and 18 published, industry-anonymised program case studies. Every rate carries its denominator: 183,524 sends in a single 10-day run in July 2025; 231,347 sends to 77,115 leads in one workspace; 163,085 sends in June 2025; 720,000 sends over six months in the mid-market SaaS program. Booked-pipeline figures (532 calls in a month, 445 calls in 25 days, 70-80 calls a week) are StoneHaven's own internal sales operation. Pipeline figures in the case studies are the client's tracked pipeline rather than StoneHaven revenue, and are never summed across programs. Open rates are not tracked, so no open-rate figure appears here for StoneHaven.

Competitor data. Taken only from each vendor's own published pages, fetched on 26 July 2026: belkins.io, belkins.io/pricing, the Belkins Fire Safety and Protection case study, cience.com, cience.com/pricing, cience.com/case-studies, martal.ca and martal.ca/pricing. Where a cell reads "not published", it means no such figure appeared on those pages as of July 2026. It is not a claim about what any vendor measures internally. No vendor rate is quoted anywhere on this page, and any range a buyer finds elsewhere should be treated as an outside estimate.

FAQ research. The seven questions above were selected from live search demand in July 2026 rather than written from imagination. Queries run: "belkins vs cience", "belkins alternatives", "cience reviews", "martal group reviews", "best cold email agency", "belkins pricing" and "how long until results from a cold email agency". Question wording follows the phrasing that recurred across result titles, People Also Ask entries and related searches for those queries, weighted toward cost, worth-it, legitimacy, alternatives and time-to-result intent.

Limitations. Vendor sites change; re-check before deciding. Belkins' 32.92% engagement figure is defined by Belkins and its exact composition is not stated on the page, so it is reported as published rather than converted into a reply rate. Martal's funnel is labelled an average production funnel on its own page and is treated here as a projection. Review-platform scores are not used as evidence anywhere in the scorecard. Industry reply-rate ranges of 3-6% are general benchmarks and belong to no single vendor. Deliverability terminology follows SPF (RFC 7208), DMARC (RFC 7489) and Google Postmaster Tools.

Last updated: July 2026.

Written by Sabo Nagy, Founder & CEO of StoneHaven. Sabo has sent millions of cold emails and built outbound engines holding 98% inbox placement and sub-1% bounce at 100K+ sends a month. Author page - X