Why use nix when pkg-src has been available on Darwin for over 15 years, boasts more packages, and has decades of support (plus Jonathan Perkin and the guys over at Joyent)? Why people assume the gross project known as homebrew (and the better macports, where homebrew gets all of their real package patches) are the only two package managers on OS X/Darwin is perplexing to me... Not to say nix is not interesting, but still. The OS X open source/package community would be insanely better if it was solely centralized around pkg-src.