I've used Subversion (SVN) and Git on Force.com projects. Either will work, but click around in the cool Github UI for a few minutes e.g. https://github.com/forcedotcom/aura (this is some of Salesforce's open source) and I suggest you won't want to use anything else. Follow the links in Jenny B's answer for the various other points of comparison or Google for more.
So if I was starting out afresh, I'd go for Git and specifically Github. (Sorry this is a subjective view not a view based on a quantitative assessment of all the options.) If your Force.com orgs that contain your source code are are in the cloud why wouldn't you have your code repository in the cloud?
The EGit tooling for Git is part of the core Eclipse distributions now too.
PS Using Git opens the possibility of making use of the Gerrit Code Review tool or release management tools such as Copado.