Fiance got me MW3 last night for Veteran's Day.
This game owns. Shooting is better, controls are better, there's a TON of recoil on BF3 and I couldn't stand it. I'm 30 mins into the campaign, i've already tore up a few blocks blazing away, used a remote drone to drop bombs, shot a helicopter down from another helicopter, now i'm scuba diving using one of those underwater propulsion things.
MW3 > BF3 without a doubt. Graphics are great, sound is great, fun factor is through the roof.
And for a year I kept telling everyone that BF3 will be way better than MW this year, i'm more than happy to pull my foot out of my mouth now.