I've really only used Clearcase and Subversion, plus some mainframe (MVS) tools that range from decent to horrific. Clearcase may be the most superterrific software product in the world, but it was horribly complicated to use. Subversion is nice, easy, friendly, and suits me just great. I use svn on personal projects, even though no one else is likely to work on them. Having a version history is the main value of a change-control-system to me. I also use it to track changes to /etc on my home systems.
in reply to My preferred version control system is...
And, of course, it has the coolest name. (Git? Git out!).