Well it's more of whether or not you want to buy the game and not a matter of should. Do you want Battlefield Badcompany 2? If you are not sure, then I would not rush to get it and check what your other options are. The only thing you'd be missing out on is another war shooter besides MW2, which you already have.
What I suggest you do is try out the demo. If you already have and your still not sure, consider looking at your other options.