worth getting
The Campaign is hard, but not hard enough to make you want to quit. Also, it has a.....well, not exactly gripping, but worth listening to. The AI is really good, and will go for cover in the right circumstances.
The Multiplayer is definitely the lasting contribution and will have you picking this game up months and even years after you beat the campaign. It's competetive, and I surprisingly found lots of people to play even though I just bought this in January.