Comparison · measurement
Sendoso, Reachdesk, Postal and PFL are real products with real strengths, and if what you need is gifting at scale, several of them are better at it than we are. This page is about one thing only: what happens when someone asks whether the spend actually caused anything.
Vendor pages reviewed 25 July 2026. These are live sites and they change; if something here is out of date, write to us and we will correct it.
First, fairly
A comparison that only lists gaps is a sales document, not a comparison. These are strong products and they are not trying to be what we are.
What their measurement pages say
Quoted from each vendor’s own site. Read them closely and the same word keeps appearing: influenced. Influenced pipeline counts deals that moved after a send. It does not distinguish the ones that would have moved anyway, which is the entire question a CFO is asking.
PFL’s is the most candid of the four, and worth reading twice: it describes itself as the thing that feeds your attribution tool, in whichever model you have chosen. That is an honest description of what every product on this page does.
The gap
This is the part we found genuinely surprising. The category understands incrementality perfectly well. It writes about it, accurately, in public. It just does not ship it.
Sendoso
“A holdout group is a randomly selected portion of the target list that does not receive a gift, used as a control to isolate the effect of gifting from other variables.”
From their own blog, May 2026. The same page separately names Sendoso’s measurement features. Holdout creation is not among them; the advice sits in the advisory section.
Postalytics
“Build true holdout groups — a segment that receives no mail, so you can measure incremental lift.”
April 2026. Their split-testing documentation covers creative against creative. A holdout is not documented as a product feature.
PFL
“you’re using matchback for directional data, holdout for incrementality, and multitouch to understand the multichannel context.”
Their own VP of Customer Success, September 2025. Exactly right, and exactly the thing the product leaves to you.
What that costs you
The clearest description of this gap is not ours. It is in PFL’s own featured customer story, describing how PODS measured their program.
A team that wanted a real answer built the experiment by hand, ran it for the better part of a year, and moved the data every week themselves. That is what rigour costs when the platform does not provide it — and note who did the work. The case study ends by calling automation a future goal.
From PFL’s PODS case study
“The team designed a true control-versus-test A/B experiment, splitting a carefully curated audience fifty-fifty and running the test for a long period of time to ensure statistical significance. They ran that test for about seven months.”
Quoted from pfl.com. Reviewed 25 July 2026.
What we actually checked
We sell measurement, so it would be strange to make competitive claims without showing our method. Here is exactly what was examined, and where our evidence is weaker than we would like.
The honest limitation: only PFL was crawled exhaustively. For the other three we can say their measurement pages make no mention of holdouts, not that the word appears nowhere on their sites. If any of these vendors ships holdout testing and we have missed it, tell us and this page changes the same week.
The category
Worth knowing if you are signing a multi-year agreement, and worth stating without spin: every acquired product still operates under its own brand, and two of the three deals had undisclosed terms.
The honest part
We are narrower than these platforms on purpose. If you recognise yourself here, they are the better buy and we would rather you knew now.
What is left is the case we are built for: a revenue team running mail as a funded channel that has to report a number someone will interrogate. The holdout testing guide covers how that number is produced, and the measurement page shows what the report looks like.
Write to us
Launch a pilot to your top accounts: research-backed pieces your reps approve, follow-up timed to delivery, and an account-level holdout that reports what the channel actually created.
Setup takes an afternoon. Delivery takes days, because paper travels. The report takes a sales cycle, because pipeline does too.
Write to us: adam@trysincerely.comSincerely,