You will NOT be disappointed. Just like all Battlefield games, BC2 actually takes some thought and skill to play. There's bullet drop physics at long distances, regular spawn points rather than totally random ones, tons of vehicles, HUGE maps, and TONS of unlockables that keep you wanting to play multiplayer. I still feel that BF2 is the best online FPS of all time, but this game may actually take that prize away.
The single player is very linear, but if you take it for what it is, a humorous little story of four soldiers better suited as cannon fodder, I think you'll find it enjoyable. Battlefield was never meant to be a single player game anyway. The character development is both really funny and well done, with all kinds of racy jokes and jabs at real life pop culture and occurrences you can relate to. By the end of the first game I couldn't wait to play another 6-7 hour campaign with these guys, and this delivers well with some nice new features and some of the most beautiful graphics I've ever seen in a game.