I tried the multiplayer beta a few months ago (Was at a 600 person LAN party that had an exclusive first crack at the beta), was REALLY not impressed (OK, it sucked the big one). However, the same friends who were saying it sucked at the LAN party have tried the single player demo and said that single player is quite good.
I've been meaning to try it, but I'm still working my way through EF2 single player, and I don't have much time for games