There are plenty of great franchises out there with incredible winning traditions. The Dolphins under Don Shula were exceptional teams. In his twenty five years with the Dolphins, Shula coached teams only had 1 losing season. While Marv Levy of the Bills is the only coach with a winning record against Shula, the Dolphins beat the Bills in the Seventies. What I mean by that is, playing twice a year from '70 to '79, the Dolphins did not lose once to the Bills.
I guess this should go in the all-time best coaches catagory.