I had my doubts with a slightly flaky open beta, but this game is definitely worth the money.
I personally think people comparing this game to MW3 are going apples-to-oranges, since MW3 is more of a traditional team deathmatch when compared to Battlefield's vehicle-based combat. The BF3 (PC) community is great, and multiplayer matches are both challenging and rewarding. You'll find that many players are less concerned with kill/death ratio than with their team winning, and the desire to work as a team generally supersedes any individual's hopes of being the top-scoring player.
As with any game your experience will vary, but I feel BF3 is best played in a platoon (BF3's equivalent of a "clan") with friends and acquaintances. Even if you're playing solo, there are plenty of decent people online to jump in-game with and enough unlocks to last me until BF4.