PS3 owners on CoD4 were really good snipers, in fact I used some of those strategies when I got the 360 version and it really helped me out ( My K/D was higher on the 360 version). But communication is key and 360 owners have mics and communicate better than the PS3 owners. So IMO the 360 owners would have the slight edge.
GamerTag/PSN ID JoshmyersBV (please add me I have 2 friends on Xbox Live)







