Im a mercurial convert; there are 2 reasons for this.
The first one is that I was experimenting with new SCM systems after falling out of love with SVN. It's just old and I needed a refresh. So I went with Git because Github was free, easy to use and feature full. But there was a major issue: the Linux Git clients were abysmal and they simply did not exist for Windows (they do now but are equally crap). I couldn't get on with any of them. So just went back to SVN in a grump.
Till someone pointed me at BitBucket.org (which is the second reason). Which is basically GitHub for Mercurial - only better! TortoiseHG works fine on windows (though needs some tweaking in 64Bit Vista...) and the command line is easy enough to get to grips with on Linux. After a few issues with multiple heads and mucked up merges (oops) I am now quite confident to use it daily.
It's been a surprise but I have started adding more and more code to my bitbucket account. Stuff I just uploaded to my FTP site previously (so I could work on it elsewhere) is now properly versioned and controlled. SVN and Git never inspired that in me.
Plus the cheapest BitBucket subscription (which gives you properly worthwhile stuff) is just $5 a month. Bargain.
Check out my sources here. So far I have Minify, Qoppa and Foxy Ikariam in public repositories.