Just released in the US. Playing on my iPad.
HOLY CRAP is this game good. Like, I think I like it more than LOL. From Tencent and huge in asia apparently, it's pretty much everything I love about HOTS and League built into one game, and actually REALLY good with touch controls. I genuinely am in love with how it handles abilities (each ability is essentially its own "stick" so you can run in one direction and cast in different directions).
Give it a shot. If more than one or two people show up ill pay to make a guild
Note: it uses Facebook as the primary network, although you can just in-game friend people as well. I'm GWJRabbit there, or Julian Murdoch on Facebook.