The gameplay in Tera is quite fun...which is good since there's really not much else. No story, little in the way of lore, nothing terribly interesting in terms of art direction, bland music, etc. That said, the action-oriented combat is a blast. I've spent 100'ish hours with it on two separate occasions now and didn't regret it.
No way I could juggle multiple MMO's right now though...I can barely keep up with one these days. Plus, I'm on a different server.