So why should you get battlefield 3, if you're already a fan of the series I dont even need to say anything, but basically Battlefield has had in my opinion, the best map designs (big nice maps) better gun balance, and ultimately a fan-base that actually respects the game, instead of exploiting its every flaw and ruining the game for the people who actually want to have some fun. If you are one of those people who likes to camp and find horribly overpowered guns to whore in call of duty, DO NOT get this game, you'll just get pissed off, and you'll piss off the fans of the series, who will shoot you in the head repeatedly until you're character decides that hes had enough and just curls up into fetal position for the rest of the map crying.
If you are one of the people like me who is fed up with COD's shit, and want a good game that you will actually enjoy for a while, instead of hastily selling it to some weird guy parked outside your house that answered your craigslist ad (best 30 bucks ive ever earned, see ya black ops) Then skip modern warfare 3, and pick up Battlefield 3 this October (Yep it comes out a month before COD too) Maybe you'll even meet me on there, ill be the one cursing out Mr. camp of duty.