Being evil isn't really so bad, except maybe for the lag.
First, the real big flaw: Thanks to the new effects NCsoft is dishing up, the frame rate, even when you turn everything down, is horrifyingly slow on ATI cards (which is what I as well as a lot of other people use). The result is one of the best slideshows ever.
But, despite this crippling flaw, COV is still a great game. I've never played any MMO ever before this, so there was the understandably steep learning curve and momentary eye gouging out.
And COV is still really well put together, maybe a bit too much. So, if you love the series, MMOs, or superheroes, you owe it to yourself to buy this game.