"Compare MW3 to MW2". Bit hard considering it isn't out. And it may be similar but it's definitely not the same.
My experience with Battlefield is how you describe your feelings towards CoD. Everyone wants to go lone wolf. Not that I'm against that, it's the style I normally play myself, in TDM only though. At least CoD players work in teams on team-based games (if everyone has a mic), BF players all tend to be like "Fuk dis shit am goin commando to take dem ****as out, back in 5 k?"
I'd still say that BF is more of a team game. If you have a good squad, with all microphones, it can be best/most fun the team play ever. Snipers covering the back and spotting enemies, Medics suppressing fire, engineers taking out the tanks etc, seems a little more "team-based" than CoDs run about shoot-everyone. Don't get me wrong, I loved CoD4, CoD5 and everything, it was just after that the whole aim of Call of Duty was lost to 7 year old Americans shouting down their microphones, only caring about quick-scopes, no-scopes and 360s. I suppose it's up to people's personal opinions, but all this shit about how BF3 is only 30 FPS and IW are using that against them, that's shit, 30FPS is perfectly playable and the only reason it is 30FPS on consoles is that they just can't handle it.
BF for the realism, war and massive maps. MW3 for the fun, fast-paced shoot-em-up.