Finally the Google Play Services integration for User Management, Leaderboards and Achievements is done!
This is a major upgrade and it took quite some time to get it done, but it is definitely worth it. The days are gone where you needed to manually enter a user name no one could ever remember.
Note that there are some more changes so far and thus you will need to re-do any of your settings in case you changed them before.
A new iOS version with Game Center integration is on its way too and currently waiting for review by Apple.