That's great, but I'm still slowly moving my projects over to Github.
1. I get much more engagement from random developers on Github. On Github, random people will fork and add features, do code reviews and leave comments. All of these things are technically possible on Google Code but nobody does it—probably due to the usability but possibly also a cultural problem. Github has a strong culture of collaboration because they strongly emphasize it in the user's experience.
2. Managing forks and pull requests is easier on Github. I want my life as a maintainer to be as easy as possible.
3. Notifications: For a long time, Google Code notifications simply didn't work for me, at all. I'd randomly stumble on one of my older projects and noticed 5 new issues opened that I didn't know about, I felt like I betrayed my users for 6+ months. Now they seem like they do, but some trust has been lost.
4. Multiple choices of documentation markup on Github is appealing.
5. The code browsing feature on Google Code feels like its own application. When you open a Github project, first thing you see is the code. On Google Code it takes 2 more clicks (that's 1 more click than Bitbucket). Think about what's the most important thing here—the code, and Github got it right.
As far as version control goes, I'm happy with either Git or Mercurial.