The game is very polarizing. Some people (and some reviewers) like it, some hate it. Its a fantastic tactical MP shooter, in my opinion. It's certainly not CoD:MW2, and people expecting some giant 256 player CoD:MW2 mashup are going to be disappointed... erm not that a giant 256 player CoD:MW2 mashup would be fun to begin with.
If you never liked games like R6V, CS, or Delta Force, SOCOM, or BF2, etc... well for one thing you are a casual shooter player, and not fit to play online with the big boys ;) ...but also you should probably just stick with MW2 and Halo, unless you're interested in expanding your horizons to include something exciting and different.
At this point, the reviews are going all over the board. That tells me the reviewers who gave it 8-10 probably liked tactical shooters to begin with. MAG redefines the tactical shooter subgenre, really. Those that give it a score in a 7s... they didn't like tactical shooters to begin with. Heck why are they even reviewing the game?