I use homebrew "for quickly assembling or installing your machine with all software automatically updated" and really have nothing to complain about. Mac OS X ships things like Python and Ruby, not because Apple envisions you will use those things to build custom applications but because there are system tools that depend on them. That's why upgrading these system packages too aggressively is a bad idea, even on Linux (and that's why RHEL is still on Python 2.4). You always have cleaner way to get and use newer versions of almost all packages without breaking the system.