I played for a while back at the beginning of the release (and for their 1 week pre-release play). At first it was a blast, but it just kind of stagnated as you got to higher and higher levels and could never get any decent planar gear because large invasions never happened on our server. The constant comment from TrionWorlds was that the server pop wasn't high enough, but they wouldn't let us transfer servers (think they eventually changed that, maybe) and who wanted to play through the same content again on a larger server, when even the massive servers were complaining about the same thing? Even played through their first major world event, but it came off poorly (not really a surprise since it was basically like one of the old Tauren stampedes from back in the old days of WoW); and as servers crashed and burned or lagged into oblivion everyone just kind of gave up. It also didn't help that they had to patch right before they took it live and everyone got disconnected so a lot of people on the more popular servers missed the entire even while trying to log on and being stuck in queue.
It wouldn't have been a big deal - I mean, we all make mistakes, right? - but the way they handled it seemed so amateurish that most of my friends and I got really disenfranchised and just canceled a few weeks after that.