I just don't like the "feel" of CoD games. They all feel the same, as they did when the very first came out. It was ok then, sure (I loved playing it online with my friends), but nowadays my bar is much higher and only certain games like BF3 meet it in terms of feel and detail.
I'm a teacher in a secondary school and I keep hearing my pupils talking about CoD as if Christmas day has come. I can see the major market here is teenagers. An interesting observation I've made however is that generally speaking, the more capable (academically) the child, the less they seem to like CoD. I make generalisations of course, based on my observations in my own school, but hey, observations all the same.