It's Star Wars and I get to play a Force user that isn't a jedi (no fun allowed!!!) for once. Better yet, I have the option of playing an Imperial even. And the non-FS classes are quite fun too.
It's nice taking on multiple enemies at once, quite a refreshing change from most MMORPGs, rather than just one or maybe two. As cliché as it sounds, it lets you feel a bit more heroic and powerful.
Finally the whole (Bioware) RPG aspect of the game is nice; cut scenes, dialogue, character/companion customization.