Missions are good the first time through. You'll see the heavy, iheavy scripting the second run-through and by the third time, you'll beat it no problem. Same thing with the original. Even on the highest difficulty, the scripting makes the game really easy.
Multiplayer is great if you know what servers to visit. Public servers are crap but if you can find a decent realism server, it gets really fun. I'm a member of the 3rd ID in CoD2 and it really changes the online experience.