Portal 2 co-op on PC

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?

I loved the co-op. Only good part of the game I really liked. Played with one of my best Interweb friends. Infact, I'd just call it, try to kill your teamate game while accidentally solving puzzles.

I loved the co-op. Only good part of the game I really liked. Played with one of my best Interweb friends. Infact, I'd just call it, try to kill your teamate game while accidentally solving puzzles.

JigglyWiggly_

haha, this is how I play every game I play over the internet.