Great game, especially if you've got 3 other rabid gamer friends ready to play. Me and my housemate are already up to the last level. I have never seen a game that swallows as much time up as Heroes. We started playing at 8 PM and when we finally looked away from the screen it was already 2:30 in the morning. That happened a couple of other times too. It's great mindless fun.
I bought it for $20 when Defender had his sale, I can vouch that its worth that price or even more.