msysgit works well on windows these days, and there are enough mac kids on github that mac support must be fine too. As far as I know, git is a bit more flexib

msysgit works well on windows these days, and there are enough mac kids on github that mac support must be fine too. As far as I know, git is a bit more flexible than mercurial, in the sense that each user can use it the way they like to (with things like quilt --- and here I'm sure someone's going to yell "but mercurial has patch queues by default!!1"), without screwing up or imposing on everyone else's workflow. I'm not sure if mercurial does this, but I can't imagine anything doing it better than git. That said, they aren't that different I don't think, so I'm sure you'll be happy either way, and each one will have its own wonkiness that you'll come to hate eventually.