If I could sum it up, it would be that the dev ux needs a lot of work, and it seems like they are mostly focused on the fundamentals of the platform first.
Following their guide you get postgres not spinning up and linking to your app correctly and you have to nuke your entire app.
The billing UI is weird and feels cobbled together.
I don't feel secure using Fly right now. But again, they are doing cutting edge shit and are probably focused on the underlying bedrock of the platform. They can always circle back to polish the dev ux.
Right now we're on Render.com and it does absolutely everything we want with wonderful dev ux.
In my mind it's a race: can fly catch up to render's UX before render can catch up to flys global mesh load balancing? We'll see who wins.