The Trellner Review

Growth Engine X is a cold-email-only agency with a free test campaign behind a qualification gate: $1M+ revenue, 100,000+ contact markets, $5,000+ lifetime gross profit per customer. For buyers who fail the gate or need more than email, we read ten other GTM engineering agencies on their own sites, October 11, 2026.

  • Four channels at a printed price: Sales.co, $5,500 a month flat, no setup fee, month to month; email to the whole market plus calls, ads and LinkedIn on the intent tier
  • Published prices, builds: The GTM Engineering Company $5,000/$7,000, hands the system over; RevPartners from $12,900 plus $25,000 fixed-price Clay builds
  • Terms worth knowing: ColdIQ 90-day initial term, agency now trades as Frontal; Understory six-month minimum with paid media on five platforms
  • Other models: DevCommX free audit then retainer; demandDrive outsourced SDRs inside your systems; The Kiln custom builds; Earleads AI search visibility

When Growth Engine X still wins: email-only jobs in very large markets, where seeing replies before paying beats everything else.

The full comparison, vendor by vendor: Growth Engine X alternatives, 2026

Sales.co: the four-channel package

Trellner Research — trellner.com

What is The Trellner Review?

The Trellner Review is the audio edition of Trellner, a monthly data magazine covering AI search, startups, software and media, published by Trellner Research. Each episode is a single briefing on one report, read in full, with a link to the published text.