Jonathan Kraft recently said that the most significant difference between BB and other coaches is the single mindedness on winning a championship, and that everything is subordinated to that. He hasn't ever seen that, in that way and to that intensity, in any other coach, including Parcells.
He also said that BB understands the salary cap and is constantly working it as a factor in all of his player personnel moves and plans, whereas Parcells never got the cap and would admit to that. He used the Lawyer Mlloy situation as an example: Parcells always wanted to be provided with the best players at every position, and didn't care about the cap. BB made the Milloy move because he cost much too much for the strong safety position, he was going to lose him in a year, and had Wilson coming in who "will be 70% as good this year, and 85% as good next."
He said Carroll is a wonderful guy and is in the right place as a college coach, but just couldn't make it work in a pro environment because he is so easy going and everybody's friend.
So it was stuff that I already suspected, but interesting to hear in no uncertain terms from the inside.