With no user reviews to balance them, the picture here comes almost entirely from founders, and it is narrow but positive. The clearest concrete feedback comes from the makers of Seagull, who say Fly.io made it trivial to launch their Golang API. Beyond that, the founder reviews are uniformly favorable but offer no usable detail on drawbacks, reliability, or day-to-day tradeoffs, so reviewers mainly suggest an easy deployment experience rather than a fully rounded view of long-term use.