As an occasional third-party Fly “shill” of sorts, I mainly talk about Fly because I’ve really wanted almost exactly what Fly does for a long time now. I’d tried other things like Hyper, Fargate and Cloud Run, but they’ve mostly been disappointing in some regards, being cumbersome to use or get started with, unrealistically expensive, or simply being too slow or limited. Fly is none of that. It still has some stuff that’s lacking; resizing disks is probably the biggest thing missing; the proxying is surprisingly complete but UDP services are a little awkward; copying data in and out is somewhat tricky, you have to use SSH but over a wireguard tunnel with an ephemeral SSH key and on Windows it’s not particularly fun. (I don’t
think SCP is supported either, which is fine, but still.) It remains exciting nonetheless because it scratches an itch that I don’t feel anyone else has really managed to; Netlify and Vercel and probably Cloudflare Pages does static sites very well, but Fly feels like, so far, the first PaaS to do any arbitrary service very well. The ability to throw Docker images into micro VMs with such ease and speed with this paradigm is truly liberating.
edit: As a note, I have not tried Render. I am sure it is fine too. I found Fly first and it satisfies my needs well enough that I don’t feel it is necessary to keep searching, though I wouldn’t mind checking it out just to see what it has to offer.