I evangelized localstack at my company a while back, but as we integrated it deeper into our CI test runs we started running into more and more things they don't support, and it feels impossible to get any attention from their support/devs despite being paying customers.

Their Cloud Pod and ephemeral instance features in particular feel pretty half-baked and not very useful at the moment.

Fun tangent: it's pretty easy to write a crack for the pro version; we actually used that for about a month as a pilot to confirm that it would do what we needed it to.