tried it in dm. whilst i still could frag with it off, i feel far more comfortable with it on and was able to headshot better. not sure if i played with it on cod4 (i think i did), but it having it on feels all natural to me.
if shadowplay could correct the 4:3 and make it stretched like it is ingame, then it really wouldn't look so bad. unfortunately, shadowplay isn't that great as of now. hopefully we'll get better things going on when the new shadowplay comes out. the beta looks promising af.