I just want to add, that once you want packages and such, for a tool chain,
you'll at least discover some problems, as there is a package anarchy out there
compared to GNU/Linux!
But
http://macports.org has a solid repository of packages.
When it comes to "private packages" packages I have found outside repos, I do install
them as "account installs", that is ~/opt/bin, ~/opt/man/man1 .. and so on, so it is
easier to upgrade the OS, and less conflicts with the different packet managers.
Having said that, most things do work, and people are friendly and easy to reach.
Most GNU packages just work, shouldn't you find what you are looking for elsewhere.
I think Mac Os X, (or just OS X now adays), is the greatest platform for free software ever!
My reason for starting out with a Mac was Applescript (http://macscripter.net) and inter application communication IPC.
I haven't regretted that a single day.