Eh, I dunno. I don't know if I'm even going to get it yet as I'm on the fence(anyone feel like trying to convince me?

). As for which side, I agree with the OP that villains are more interesting than heroes....when done right. A lot of times they're one-dimensional and bland, simply a cardboard cutout stand in for the heroes to rage against or evil for no other reason than being evil. Though, this is Bioware, so I suppose I should give them the benefit of the doubt.
Edit: The one thing that will piss me off more than anything is if I play Sith and the amazing, wonderful, in-depth storyline the whole game is supposed to have turns into "Herpderp ill kill you cuz im ebil" Being evil for the sake of evil is boring.