Also known to install FBI backdoors:
http://cryptome.org/0003/fbi-backdoors.htm
-25 karma · joined February 1, 2011
If you're ready for the real thing - go for straight up FreeBSD. They are extremely organized, you can go to one site for all of your questions, everything is well documented. They have pre-compiled third party binaries available known as packages in addition to all of the source which you can compile yourself. There is also a 'Linux compatibility mode' so that you can run Linux binaries.
I personally prefer FreeBSD over Linux.