I've played it. Hardly anything better than Rogue Leader. It has more characters on screen, sure. But it moves at a somewhat sluggish framerate. Not to mention the missions consist mostly of 'Destroy Target, move to next area, beat game." Multiplayer is good, if you do have more than you and your friend.
However, my Target had the game for $20. I would probably say its a good buy now. It was okay. But when Rebel Strike comes, this'll definatley knock it off of 'Best Star Wars Multiplayer GCN game'