The review itself is only part of the transaction. You are also buying the outlet’s standards. If those standards are weak, your finished review may not be usable where you need it most.
A good place to start is this piece on why IndieReader’s AI issue matters to authors. It lays out the trust issue in plain English and explains why a review that looks fine at a glance can still be a problem.
Every service should be able to answer three things: what their AI policy is, how they screen reviewer submissions, and how they handle rewrites or refunds. If they cannot answer cleanly, keep your money.