Running (diskless) production workloads on Fly.io since 2021 (300+ req/sec across 30+ regions). Sure you ran into problems almost every month back then, but not anymore. Not in my experience.

I did have my postgresql DB on their service randomly stop once and didn't restart until I logged in and poked it :(

I also don't use fly (yet) because of technical issues they have. They are in a really messy state at the moment.

Nevertheless, I'm excited for them and continue to cheer them on until they mature.