Ubisoft doesn't mind competition

As I'm sure you are aware, Ubisoft's Assassins Creed: Brotherhood is the third title in the series, it is also the third time that the franchise will be directly butting heads with Activision's Call of Duty franchise.

A Ubisoft PR representative had this to say: "Every major Assassin’s Creed title has been released in November, and the series has obvious done incredibly well in that position. Given that track record we see no reason to move the launch date of the third entry in the series regardless of any competition."