The one time we played the cooperative game, we didn't like it very much. The game is arguably best in solitaire mode, and whether you play it with others in co-op or competitive mode, the solitaire feeling stays with it. So in co-op mode, you're not really cooperating on anything - there's no real way you can help each other - you're just... not competing.
The expansion may contain scenarios that improve the co-op experience, though.
The expansion may contain scenarios that improve the co-op experience, though.