CoachCheckIns runs one part of your week, the weekly client check-in, so the honest question is whether you want a narrow tool beside your programming or one platform that swallows everything.
Most independent trainers do not lose clients in the gym. They lose them in the quiet weeks, when a client stops replying, skips two sessions, calls it a busy month, and then sends the cancellation note on the first of the following month. Every tool below touches that problem from a different angle, and the right pick depends on whether your programming and billing are already settled or still moving.
The comparisons here stay at the level of scope and workflow shape. We describe what kind of product each option is and the sort of coaching practice it assumes, not their prices, plans, or feature lists, because those move and you should read them from the source. What we can be specific about is CoachCheckIns: automated weekly check-in forms, an adherence score per client, and at-risk flags, on plans at $29, $59, and $129 a month by roster size.