Among the series, this has the best campaign story for me.
It's still fictional but since Black Ops is based on real life events especially during the time before I was born and where I only heard them on books or other media it has a certain realism to it. It made me liked the game.
I don't know about other CoD games, but when I aim down my sights on my SCAR, one thing I noticed is that the sight moves with me. Try it so that you'll know what I mean. It's another plus.
Another thing is that the weapons found here belong to an era decades ago(maybe most). It is a bit refreshing for me not to look down at a laser sight. And there's that damn H&K rifle, the one with the rectangular futuristic shape. Last I seen it in a game was in the Playstation One. I like.
The graphics are superb. I can see the sweat and pores of my NPC buddies. And combatants spurt blood or will lost a limb or two when hit. Which make me like Black Ops a little bit more.
As for the game that it really is, it's a thoroughly enjoyable shooter. Plus the zombie mode bit made it a little bit more enjoyable. It's a break from the ruthless FPS gaming.