I never much cared for 2, and I bought 3 a while ago, but played the first level and haven't picked it up since.
I did, however, play the multiplayer on 2 with a lot of my friends at LAN parties. A 250 kill rockets/brute shots/grenades match on Foundation (smallest map in the game) with 8-16 people is a mess, but it's the most fun you'll have on that game, especially if the people that are playing are creative when it comes to names.