Awesome game.
This game is full of different weapons, different for air, and land.
Expansions keep this game from getting old.
Multiplayer is seemless.
Nice and simple setup, learning curve is about 20 minutes.
The Bad:
Game lacks single player campaign which would have probably been a lot of fun.
Without expansions, you'll quickly know every rock and groove of the three maps you start out with.
Review:
The game is very easy to learn, in twenty minutes anyone will know how to play, and with an hour or two of practice you should be on par with most people online. However, there is always someone online that will challenge you, so it never really gets boring, there are several different playing modes that really keep you on your feet. Lot's of people aren't as good with all of them as they are will a specific one, so if you alternate, you are balancing the playing field a lot.
Bottom line:
I recommend this game. It's really fun.