I've been playing it a bit and did go on OCE when there was really long game queues on NA the first day. I believe that ranked is coming out pretty soon so it will be interesting to see how fun that is.
P.S. I can win most games by tunneling assassins + ninjas. (If you have a really good game you can use force of nature or get level 9 and add a swain for imperial + demon bonuses)