Got both..
My opinion, BF3 is better..
The reality, I regret buying it. Been playing MW3.
If I want something serious, ill go buy a gun and start shooting my enemies. Right now, i just want a fast paced game where I can shoot everyone possible with sound effects and crazy music each time I level up and be able to put 5 attachments on at once and pimp out my gun and have 10 different kill streaks..
...why cant I want that?