Battlefield 2 Modern Combat is awesome online.
Pros: Online, Online, and Online. Don't bother with the single player unless you just want to unlock crap. The online is so intense... You'll be standing out in the middle of no where when all of the sudden you'll have to run from a crashing helicopter. The weapons are beautifully detailed. The graphics are pretty damn good. The controls aren't like a standard FPS, works better this way. Vehicle combat is great. The music is FANTASTIC and really puts you in the mood. Charector movement animations are very realistic and the physics to the game are very fun to watch (Ex: Watching a dude fly like 50 feet in the air then smack the ground after you C-4'd his Hummer). Every Xbox Live game should follow this games multiplayer format. It's easy to find games and stay with them... Sides are usually pretty balanced... Rank can be turn on or off very easily (unlike PDZ)... No major lag issues (unlike COD2)... Laser guided missles from the Sniper class, and artillery from the Support class are both great additions to the Battlefield Arsenal. Charector classes very well balanced, feels like no one class has an advantage. This game is probably the best online game Xbox 360 has to offer.
Cons: Why is this called Battlefield 2 again.... it's a totally different game from the PC's Battlefield 2. C-4 is not strong enough to destroy a tank..... Waaaaaa???? That was half the fun on the PC version, strapping C-4 to a truck and suicide bombing a tank. Also, you can't look around in vehicles like you can on PC... thats a cool feature and should be in this game. Also something cool at the PC version thats missing here.... The Medic class and it's cool paddles.... nothings better than saving your troops lives then zapping someone to death. Squads are missing too..... WHY!
Final word: Tons of action online. If you have live buy it.... If you don't, I wouldn't bother. Definantly one of those online experiences that keeps you coming back again and again. Just don't expect the game to be better than it's PC counter part.