This game is not as bad as everybody says it is! Its not perfect but I found it enjoyable for the most part
Campaign - A great conclusion to the modern warfare trilogy, the action was fast paced and the story while over the top and far for perfect managed to wrap this trilogy up nicely. Unfortunately it still has the annoying issues of past campaigns, its short, enemies infinitely respawn and there are some cheap deaths but its way more fun than BF3's campaign.
Spec ops- MASSIVE improvement over spec ops in MW2 with new missions to take part in, survival mode is awesome and the separate progression system is a nice idea. Main issue is that its 2 player only unlike Nazi zombies which has 4 players, thankfully it includes matchmaking which should get more people into it.
Multiplayer- Unfortunately the multiplayer was disappointing, I was looking forward to the multiplayer since it would take me back to good old MW2 days minus quick scoping, FFA boosting, nukes and commando/marathon whores. Whilst some of MW2 major issues have been ironed out not all of them have quick scoping is back and worse than ever, connecting to the servers takes too long (maybe my uni nerfs it intentionally but I'm not sure on that) and whilst the weapon levelling system and strike packages are cool ides people will still whore out the same one weapon and perk over and over which are massively overpowering (e.g. BO Ghost / ak 74u) and the new modes are just neat little variations of older modes. One of the good things include the custom options in private matches, with plenty of options for custom mode makers it can be pretty fun. But it doesn't make up the fact that MW3's multiplayer is severely disappointing, in fact after playing I played about 3 or 4 matches of MW3 shut down my ps3, turned on my PC and launched BF3 for hours on end.
Overall- MW3 is more of the same from MW2 but it doesn't automatically make it a bad game, the campaign and the spec ops modes are very enjoyable but the disappointing multiplayer let down the overall package. Multiplayer FPS fans should pick up BF3, if you want a great campaign and fun co op and if you can enjoy the multiplayer you'll enjoy it. If you want the best COD get COD 4 but this isn't a bad game so don't follow the 95% of trolls that bas a game that they haven't played to and promote their Youtube channel!