Right now I'm on github -- for about 2 months now. The integration with Visual Studio is simply amazing!
I used to be on bitbucket (mercurial), until they announced they would no longer host it. I tried to convert it to git - even though manually doing it is not very pleasant. But now they have a 2GB limit which I almost reached -- that ended up being a huuuuge no-no for me, because I would clearly reach it in the short term.
So, I've created a new repository on github (could not successfully import the one from bitbucket), and I'm still keeping the old (ported to git) bitbucket repository for historical reasons.