The most annoying problem with Google Code is they refuse to have private paid for hosting - https://code.google.com/p/support/issues/detail?id=1829
Having all our employees create new Github accounts and doing administration there is a pain when we already do everything else at Google. I suspect paid project hosting would also help improve Google Code since there would be revenue behind feature requests and bugs.
With Google Code you can have any number of additional repositories eg the equivalent of github.com/[user]/[project].documentation.git, github.com/[user]/[project].testsuites.git, github.com/[user]/[project].androidclient.git etc
With Github you would have to create new projects which means separate issue trackers, wikis etc.
[1] http://blog.bitbucket.org/2012/07/26/issue-tracker-user-inte...
I did have some unpleasant experiences though, including a security hole (since fixed), which didn't leave me with much confidence.