Feature that truly impressed me, something rather rare:
You can set different devices for audio and voice, like you can for most voice communication applications (Teamspeak, for example). Doesn't make a difference for most, but does for some like me. Audio from the game comes over my soundcard and out the speakers, while voice goes in and out over my headset plugged into the on-board soundcard. Keeps things nicely separated.
Also, you have volume sliders that override the volume when recieving voice, dampening music and sound-effects to make sure you can hear it clearly.
Very nice features. Most games don't really bother with a good sound engine.
