In recent times, I've noticed a horrible trend of games being released via Steam that rely on Steam's VOIP for in-game voice chat. I couldn't tell you why, but unless it's a Valve game, they seem to have extremely poor implementations. Very recent games I've seen this problem in include Monday Night Combat and Homefront. The volume of incoming chat is usually inaudible and/or muffled. Often times push-to-talk doesn't work - only voice activated. Furthermore, most developers don't seem to put much effort in to offering a visual indicator of when someone is talking or who is talking.
It would be nice to get some official word on these aspects of VOIP for the game for PC users. I think it's a very legitimate concern. Though, I suppose I could just wait a week and find out from friends.