12 minutes of Battlefield 3 even at 30fps It has my money.

MW 60FPS Battlefield 30FPS. So what I say.
Having seen both the Battlefield and MW footage, and being a long time fan of MW, I'm not ashamed to say that Battlefield has the clear advantage - for a whole host of reasons that makes the framerate redundant. 
choice of footage - this alone is significant because is reveals how closely attuned the developers are to what grabs the gamer. 
Then there's the characterisation. The DICE advantage gives teamwork, battlefield clearly places you as a member of a team. Add to that, a team of characters that are made credible through their appearance, behaviour and expressions. By comparison, MW gives you visual action alone. 
Dice were smart enough to use gameplay footage that drew the prospective player in as being part of a story involving people the player felt connected to, right from the off. Very smart marketing. 
To the eye, Battlefield looks visually more impressive. You don't need to be 'told' with a graph that MW is better. Ignore the graph to look at the screen and what you see isn't as gritty and doesn't appeal as much as Battlefield. Battlefield delivers a visually more (from a gaming point of view) combat realistic experience. 
And I think this is the dealbreaker. It's what Killzone banked on and it worked, twice. 
So, it may well be that the Frostbite 2 engine is only half of the MW delivery but it's more than capable of delivering a better visual experience all round by virtue of it the story, where it puts the player and the way the story is told. Frames per second don't amount to a hill of beans, beyond 'Hey this looks great'