According to industry analyst firm Cowen & Company, Battlefield 3's pre-order numbers are "roughly comparable" with the pre-order numbers on Call of Duty: Black Ops. The results of these pre-order numbers is that the firm has now decided to increase its first year sales estimate from eight to 11 million.
Black Ops sold around 20 million copies in its first nine months on sale. Battlefield 3 may be keeping up with Black Ops, but can it compete with Modern Warfare 3? From a game point of view, yes. From a sales point of view, I think no. I think the Modern Warfare series has become a shadow of its former self.