git and Mercurial are both based on similar principles (distributed version control systems). I found when I did a comparison a few years back that Mercurial did tend to have a more consistent interface and the tools were somewhat easier for new users (particularly Windows) to pick up, for the community I support. Wha clinched it was a comment I read from one of the original authors of the O'Reilly book on Subversion who works for Google, who made it clear that he uses Mercurial exclusively for his non-work projects.
That said, they'll both do the job ...
hginit.com is a good place to start with Mercurial.
Peter.