Great dvcs. Easier to pick up than git (especially if you are used to svn), although perhaps not as powerful. Has much better support on windows so use if you plan on doing any cross platform development.
Used Mercurial to download the entire 700 Mb of Google's font directory. Simply followed the directions at http://code.google.com/p/googlefontdirectory/ except used Software Manager to install Mercury. Quite easy. Thanks.
Being new to Linux and coming from Window's Subversion Tortoise I thought I might run into trouble... but this versioning system is so easy to setup and use that I don't even bother grabbing a GUI frontend for it. Checking out, commits, branches, and merges etc are such a breeze. Love it so much I even ditched Subversion in favor of Mercurial + command prompt when I need to work from a Windows machine!