Cloud Flare's model is to give you "unlimited" bandwidth with restrictions on how you can use it. If you do any kind of volume you quickly get a call from a sales person who wants to sell you enterprise. And then you end up paying a relatively high per-GB price as one big enterprise contract.
They're reasonably transparent about this, and I think it's fair. It's just not how I prefer to buy services.
At no point will we call you up and try to get you to spend more money to keep doing what you're already doing.
We are pushing xxTBs every month at this point, and I haven't got the call yet. I'd have to spend $yyyy dollars on Fly.io for that kind of bandwidth. By simply moving to Unbound last month, we even halved our bills, and with some planned software changes, bills should go down another 30%. Besides, Matthew Prince says pushing higher bandwidth via Workers is fair game [0].
That said, I very much prefer Fly.io to AWS for workloads not suitable for Workers... and in just these past 3 months, we committed eng resources to make sure Workers workloads can run on Fly.io too, if and when the time comes for an instant migration.
We also run workloads on AWS AppRunner and Amazon Lightsail Containers and that's only because S3 <-> EC2 bandwidth is ~$0. We'd definitely move to R2 once Cloudflare opens it up, and we hope, eventually, Fly.io reaches the scale to peer directly with Cloudflare DCs for lower latencies, if nothing else.
They're reasonably transparent about this, and I think it's fair. It's just not how I prefer to buy services.
At no point will we call you up and try to get you to spend more money to keep doing what you're already doing.