Interesting, I've only ever used it on Ubuntu, both with the system Debian packages and with versions built from source (via Opam, the OCaml package manager). Both were rock solid for me. If anything, my understanding is that it's Windows where things are sketchy (for OCaml in general, not Coq specifically). Anyway. I'm sorry to hear you had a bad time. It's probably no consolation that it doesn't seem to be as bad for most others.