Best part of SWTOR no xmas event people like me (I may be the only one) that not can stand this Holiday can finally play a MMO in the holiday season that not remember me every minute about Real world holidays I try to get away from! Thanks Bioware!
I find the best part of SWTOR to be the great balance between familiarity and unfamiliarity. The game is a blast to play because it's a new world... err universe, new stories, new challenges. Yet the game is built like a standard mmo (or like WoW) so it's able to be picked up and played without much learning curve. I'm with basically the same people I play with in WoW, but everyone's attitudes is different.
Though the same things could be said for Rift. We all played that game as well and it was new and not new at the same time, yet no one really had any fun. So I don't know what the difference is.