Fly looks great to me, though I've never had a chance to use it. For what it's worth though, Cloud Run on GCP is one of my top 3 favorite infrastructure/deployment tools, so you're setting the bar pretty high.
Why would anyone choose a provider that is inferior (apart from toying)?
I mainly read two kind of stories from fly.io. Their promotional, but well written and interesting technical blogs like this one and stories about issues with their services and miscommunication. So, despite liking their blogs I don't consider using it.
Part of the reason I stick with Fly.io is because I want a rock solid version of what they do to exist, and they're the most likely people to eventually get there.
That said, I've had very few issues with their platform, and I don't think it's ever caused downtime for my (admittedly very small) service.
Why would anyone choose a provider that is inferior (apart from toying)?
I mainly read two kind of stories from fly.io. Their promotional, but well written and interesting technical blogs like this one and stories about issues with their services and miscommunication. So, despite liking their blogs I don't consider using it.