A40: -wires (if you play close to TV) -Mixamp to control Master volume and game/voice separately -Can plug mp3 into Mixamp -can stream game through Mixamp (if your using some other hardware/software) -powered by USB -comfy A50: -same as A50 but $300 for wireless -if you have kids/people over etc good for that -battery life is about 7hrs on a 1hr30 charge time (mine were bought Nov. 2013) but new pair I believe STATED to be 10hr battery -comfy and are fine with glasses -solid headset