I put a vote up to integrate Google Play Game Services into Unity on Unity Feedback. I think Achievements and Leaderboards are a vital part of todays Games and since Unity Social currently only supports Gamecenter i feel a little left out as an android developer 
Cool idea… u got my vote 
It would be really useful and awesome, if this would be integrated :).
We’re up to 34 votes now, gj guys.
I just wanted to publicly answer to a pm i got: I am aware that there is a Plugin by Prime31 for sale to achieve this functionality, but i don’t see any reason why you would need a plugin for android when you don’t need one for ios :).
Vote up by 9… We are juts ONE Vote behind… 
Given this 10 votes.