I've using Bitrise for a few years and it's one of the few tools in my stack I don't think about, which is the highest praise I have for infrastructure.
The mobile side is clearly built by people who ship mobile apps. New Xcode versions turn up fast, the stacks are kept clean, and the stuff that usually breaks on mobile CI breaks a lot less here.
RDE is the first new thing in a while that actually changed my day rather than just making builds faster. A real Mac with the right setup in seconds, and I can hand one to an agent and let it get on with it.
Support answers fast, and they tell you straight when something isn't supported.