How is it? I have been wanting to buy Portal 2 since the first one was awesome, but I've heard/read that co-op is a large part of the game. It sounds awesome, but I don't have a PS3 or 360 so anyone I'd be playing with would have to be online, or would also have to have a copy of the game... right? To me, playing co-op online doesn't sound nearly as fun as playing in the same room with somebody, but maybe it is.
More simply put, three questions:
1) Is Portal 2 co-op on PC fun?
2) How does it compare to co-op on the PS3/Xbox 360?
3) Do you think it would be worth buying the game just for the single player experience?