Possibly not, but I would assume that any date they announce they will be certain they can hit. They've always maintained November though, so any release earlier than originally planned will only be by a few weeks, so they're not jumping the gun that much.
I guess, or at least I'd hope that a company like Microsoft wouldn't release something they aren't sure about just to beat the competition
I wonder how things would go down if they announced a release date in the EU for the 15th November, get the attention of those who are too impatient too wait until the 29th for the PS4 and possibly jump ship (I know some people who would probably do this just to avoid the wait).
