I personally am on the fence about it. I know a lot of people are growing tired of the series due to yearly releases. Also people say it is basically the same game with some new maps and guns each year. However, I think if you compare it to yearly sports games the CoD series seems to at least innovate more than that.
Another reason is that it is a major time sink for me. They are games that you can potentially devote 100s of hours to. The games can be rather addictive. Addiction is not always the sign of a great game, and I think I might be better off playing a slew of single player games instead of so much CoD. If I do get it I am going to try to limit how much I play the best I can.