MP is the main attraction of Bf3 along with jaw-dropping graphics. I can't give you any assurance that the Sp campaign will be awesome but it will surely be a good one.
If you are looking for awesome multiplayer experience then BF3 is the game for you. Also 1.5k for SP only is not worth it IMO. If you get the game, make sure that you play the MP as well.
And talking about graphics, you can easily rule out Mw3 and C2 from the debate. Period.
Because Mw3 is based on the same crappy engine that they have been using for COD games for years with little improvements.Although, the SP will be kick-ass undoubtedly. And C2, it may look good, but it failed it deliver, both in the SP and MP.