Comment by peatmoss

> until you've had to use autotools or custom build a makefile for a half dozen different C compilers, kernels, libc, and so on, you don't know from POSIX "standards" pain.

Truer words have ne'er been spoken. My first big boy job involved building and maintaining a large open source stack on top of AIX. These days I occasionally experience hiccups related to OpenBSD not being Linux. Problems aren't even in the same league. That said, the thrill of getting stuff to work on AIX was certainly greater (and purchased with more human suffering).