Game sound effects directly into your ears is superb, you really can here things you can't through your TV sound system. Can't say how it performs agianst surrond sound systems. But in the COD series you here foot steps earlier, clearer and with left or right direction. This does help with multiplayer games.
Dead Space or Allan Wake with the lights turned off and head ohones on with sound up high, I guarentee the hairs on your neck will stand up. Sound makes the difference to the atmosphere of the game.
Voice control again is excellent. Talk to your mates, turn up thier volume independantly or better still turn off the idiots and concentrate on the game play.
Can plug directly into you TV (slight hiss can be heard, think it's my TV) you can here your TV, video, cd, blueray etc that is plugged into the TV.
The wireless is excellent, I sit between 6 and 10 feet away and move around and they work without and issue.
I now have in my house 2 pairs, one for my son (x11's) and now I personally have x31's.
Gamer? Buy a pair....