Played Rift for a couple of hours last night. It's pretty cool. It's a lot like WoW but with several interesting twists. There are only 4 classes, but with the soul system there are effectively a lot more than that.
I think the two factions are interesting and pretty well defined. The Guardians have the support of the old gods and are from the past, the Defiant are technology based and come from a post-apocalyptic future. (I rolled Defiant)