-The sound quality is excellent. Unfortunately, good quality depends on the speaker, not the listener. This means people will be able to hear u very well, so you at least you know people will listen to you.
-Once again hearing other players depends on their mic. But having this headset will only help.
-You won't be able to hear enemy footsteps around you. You would need a surround sound headset, which usually costs a lot more. That, or have actual surround sound speakers. I have them, so I'm satisfied with the official headset
But if you really want to improve your game in MW2, then I suggest searching for surround sound headsets. I believe the commonly used ones are called "Turtle Beach" or something like that