Man is it bad. I just finished playing with some forumites, and the game was barely playable. That thing was just chugging. And it's not like it's heavy traffic time--it's 11:30 on a Sunday night after all. Every other game can be lag free so why not this one? Heck, even MOHH2 was pretty much lag free, and that game has WAY more going on that this game. This game should be a piece of cake to get running lag free.
Get on it Nintendo!