I would happily switch to it in a heartbeat if it was a lot more well-documented and if it supported even half of what CMake does.

As an example of what I mean, say I want to link to the FMOD library (or any library I legally can't redistribute as an SDK). Or I want to enable automatic detection on Windows where I know the library/SDK is an installer package. My solution, in CMake, is to just ask the registry. In XMake I still can't figure out how to pull this off. I know that's pretty niche, but still.

The documentation gap is the biggest hurtle. A lot of the functions/ways of doing things are poorly documented, if they are at all. Including a CMake library that isn't in any of the package managers for example. It also has some weird quirks: automatic/magic scoping (which is NOT a bonus) along with a hack "import" function instead of using native require.

All of this said, it does work well when it does work. Especially with modules.