I managed to get it compiled entirely with clang, but for the fact that clang doesn't have 16-bit assembler support (yet).

I really like it for the fact that it's the bare essentials of a complete kernel. When wondering how, for example, scheduling works, this is a much better idea on how the mechanics work. Obviously, the algorithms used might be far more sophisticated in a modern, production kernel, but that's not why you would use X6v.