I was an addict, Treyarc may have cured me.
I know a lot of people get COD just for the single player and that is one thing this game delivers on. The pacing is well done, and the old adage that the graphics are dead is not entirely true, still a pretty game despite the ancient engine. They also gave the it replayability in the way you can score each mission and then compare with friends. You also can choose your own loadout. The one downside is the strike missions, interesting concept but your better off doing the Rambo thing and letting the A.I. figure the rest out.
As far as Zombies goes they didn't do anything amazing with it, just enough to keep it from being to stale.
Now for the 100000 pound gorilla that is MP. The weapons feel good and sound good, only problem is the balancing. Every match 9 out of 12 people are running around with smg's. They removed the perk tree and kept it simple no pro perks. The only problem is the smg is quicker to aim and with no effort to balance that the stupid things rule the day. The pick ten system is a lot of fun to mess with, and the calling cards are a good reason to keep playing and prestige, no copy and paste there, the cards are orignal.
The maps in my opinion are truly terrible. I am not sure what they were going for but there is almost no straight lines of sight. A million places to camp which is worse so far than other iterations. The spawning is beyond bad, spawning with two other teamates next to a guy that died a millsecond ago just doesn't work, so tired of the spawndeaths. MW3 was the first one I didn't prestige all the way, only 5 times, and unless they nerf the smg's this will be it for me. I was a constant 2.20 K/D on all CODs without camping and I can't break even, really doubt I woke up yesterday and all of a sudden couldn;t play.
Oh and by the way, it's crashed my PS3 5 times so that in itself makes the game a questionable purchase.