Only issue stopping me from using Fly: bandwidth costs. I am spoiled by DigitalOcean's 1TB tier per droplet created (along with bandwidth pooling if you have more droplets).
That's true but Fly's PaaS is perhaps more comparable to DigitalOcean's App Platform (its PaaS). For that, DO include 100GB for free while Fly include 160GB. Beyond that, DO charge $0.10/GB while Fly charge $0.02-$0.12/GB. Cheaper bandwidth for Fly's Machines (more comparable to droplets, as far as I can see) would be neat though.
Yes I agree that Fly's PaaS is more comparable to DO's App Platform and definitely has better price model. However, I don't use DO's App Platform for exactly the same reasons as why I don't use Fly's PaaS. I like services which provide bandwidth for cheap (or even free — Cloudflare Images and Cloudflare R2 comes to mind). Ideally, I want to be charged only for features I use and not for egress which I have no control over. But I know that is not feasible from business point of view (unless you are Cloudflare).