I also wonder why so many people forget about bitbucket. To me really it's the matter of taste, and there is certainly less differences between github and bitbucket than there is between git and mercurial.
I managed to convert a few Github paying customers to switch to bitbucket. The only reason they state for using github was that they didn't know bitbucket is available for use with git (as well as with mercurial) besides the private repos thingy.
