BF2:MC is a great game. I only recommend it if you are going to play it online, though.
Battlefield 2: Modern Combat is a unique game. The multiplayer and the single player modes are different. I only recommend this game if you are going to play it online. The offline mode is about average, and probably not worth $40.
The gameplay of the game is very good online. Offline is not nearly as fun as the online mode is. The game is 24-player online, and has clan battles. One could arrange a series of clan battles, making your own tournament! The controls are simple and easy to learn.
I'm not very picky when it comes to graphics, so I gave the game an eight under graphics. The graphics are not revolutionary, but they aren't bad. The sound isn't spectacular either. I usually don't notice the music. The sound affects are good.
The replay value of this game is the best part, in my opinion. The single-player campaign mode has extra challenges, field tasks, and medals for you to complete/unlock. After each mission, you will get graded and earn stars based on accuracy, time, deaths, etc. As you earn more stars, you earn more ranks, challenges, weapons, and weapon upgrades.
The replay value of the multiplayer mode is also good. You could play battle after battle after battle and not get bored. There are ranks in multiplayer mode, too.
Overall, I think that this game is great, but rent it before you buy it. Try the online mode out before you say no. If you liked Star Wars: Battlefront 2 or the original, then you will probably like this game, too.