Here it goes:
-Mediocre Campaign: The Campaign looked promising in the trailers and demos, but it failed to achieve much. It gets very boring after a few short missions, the game on normal difficulty is WAY too difficult, and the ending is just terrible in my opinion. It has its moments, but not enough.
-Decent Co-Op: The Co-Op missions are alright. Nothing out of this world, but worth a playthrough with a friend. But he best part of the Co-Op mode is that you can unlock exclusive weapons for the multiplayer via Co-Op.
-INCREDIBLE Multiplayer: Like all of the series' games, the multiplayer in BF3 is fantastic. The maps are large, open, and unique. And the Jets are a huge reason to keep playing, and the amount of unlocks in the game is enormous. The MP is just fun. Period. It beats all of the other multiplayer offerings found in the entire franchise and it is by far the best multiplayer game since COD4 and Halo 2.
-It sounds and looks like you're actually in a Battlefield: Fan-freaking-tastic sound design. When a jet activates its afterburners as it flies right above you, you WILL be impressed. The graphics are a bit of a let-down for console users, the game does not look very similar to what you've seen in the trailers.
-Great Gameplay: The game fuses the best features of Bad Company 2's gameplay and Battlefield 2's gameplay to create something very fresh and new. It's not perfect though.
The game's campaign is a pretty weak and the Co-Op is a nice addition. But the real reason to get this game is the Multiplayer. If you don't have a PSN or Xbox Live account and plan on buying this game for its single player, don't. But if you are able to play this game online, there is absolutely no reason for you to skip this game. Its well worth the $60 for the MP alone. Buy this game, you will not be disappointed.