Fly's been many things over the course of its lifetime [0], but I believe their latest pivot (on what they call "Machines") is pretty darn good. I've been using Machines since Oct last year, and things have gotten better week-over-week. Like with any platform, Fly has its own idiosyncrasies, which don't take much to get hang of. That said, I am the only person in my tech shop that deals with Fly. Some orgs with larger teams and heavier apps that deploy frequently or run DBs / disks on Fly (I don't) have had a rough few months; so that's there too.
Honesty pays off in the long run, but it's something businesses quickly forget past a certain stage.
Machines isn't that. From the documentation, it appears as though it's "just" a VM pinned to a single region and none of the "magic" of Fly really applies. If the server your VM is hosted on goes down, Fly won't redeploy your container. It's just downtime. Spinning up in other regions is something you have to think about and actually do. It seems closer to Heroku than it does Fly.
Maybe I am totally misunderstanding Fly Machines and their use-case, maybe they're aiming to close the gap between Machines and Fly apps. It's just a bit of a bummer to see something that looks like walking back the original "promise" of Fly and makes me question whether or not Fly is going to just become like every other PaaS (even if it's a really good one).
Even without autoscale, spinning up Machine clones in any of the 30+ Fly regions is as easy an instant scale-out you'll likely come across on any of the NewCloud platforms.