Also... MW3 is going to be bad right now because all the hardcore headz are playing with their friends trying to level up quickly = more of these kinds of dominant groups running (ruining?) a whole game.
The comment about no 50-2 games in BF3 is bang on. It's not about kills. I often have negative k/d but still am leading my team. And I couldn't care any less about that.
BF3 is painfully slow to unlock new gear though... I'm already having fun with new guns/perks/etc in MW3...
Different games for different moods...