SourceTree | Mercurial and Git GUI for Mac OS X. That looks really good - although 45 euros is not exactly cheap. However, it can handle Git, Mercurial, and Subversion, so maybe I should take a look at it (there is a free trial version). Update: Short test by me and I really like it - you can integrate external diff tools (Changes is unfortunately only supported as a diff, not directly as a merge) and always have the same interface, regardless of which server is behind it. This takes away some of the pain of Git. Version tools are included internally, so you don't even need to have the command line versions installed. Looks really interesting.