I recently started using Fly to host the anycast DNS name servers for my DNS hosting service SlickDNS (https://www.slickdns.com/).

There were some initial teething issues as Fly only recently added UDP support, but they were very responsive to the various bugs I reported and fixed them. My name servers have been running problem free for several weeks now.

The Fly UX via the flyctl command-line app is excellent, very Heroku-like.

For apps that need anycast the only real alternative to Fly that I found is AWS Global Accelerator, but it limits you to two anycast IP addresses, it's much more expensive than Fly and you're fighting the AWS API the whole time.

You can get a reasonable idea of the problems people run into on our community forum. I use Fly for everything but that may not be the best signal for you: https://community.fly.io/

I recently setup my own http://logpaste.com to give them a try. Fly was quite easy to use.

Love Fly. Been using it for about a year now? We host Draftbit in a bunch of regions. The community is growing and they know their shit.

I use fly to host a few apps and its fantastic. Extremely responsive and it handling TLS offload is great from a performance perspective.

I find their billing dashboard leaves a bit to be desired, I'm still very nervous I'm going to get a big unexpected bill.

I discovered fly a month or two ago, and I've been incredibly impressed. The dev experience is really nice, and the team is super responsive.