Got invited and finding this surprisingly good, even though I didn't care much for DOTA2, LOL, HoN, or even the original DOTA Warcraft mod. Probably played about 20 - 30 games of each whenever they were released and just lost interest. I dunno, shared XP and getting rid of tedious mechanics like last hit are good changes imho. Games are shorter too. The tutorials are way better than every other MOBA game (at least back when I tried them). Mounts are a cool addition and can't say I really miss managing inventory either.
Coop mode is nice for trying out heroes, I don't remember that being an option in LoL or DOTA2? Not sure ...