Right, well, judging by the sales figures, you've played this already, so I'll be brief. The single player is the most cinematic FPS experience ever created, as well as the most epic, and is absolutely thrilling from beginning to (way too early) end. Said ending is also one of the best "boss fights" in an FPS ever. The multiplayer is exactly the same that we've seen in CoD4 and CoD5, but with a few new things and a polished off experience. The Special Ops is surprisingly fun, with the stealth and sniping missions being some of the best Coop play out there.
But you know this already, don't you?
In a sentence:
The best CoD yet, and a new benchmark for FPS. The single player is short, but a must-play.