I don't really know. I wouldn't rank him as high as K, Pitino, or some other guys. But, I certainly think he's a very good X and O's guy. So, he'd rank in the upper-echelon, but not the best, imo.
Disagree and many others disagree. He has choked with some of the best talents in CBB. All those great players he had in Kansas, yet could never win the big game. Then was given another gold mine in Carolina with I believe at least 4 NBA first round picks on both of the championship squads.
I would take
Pitino
Calhoun
Huggins
Boeheim
Coach K
Izzo
Stevens
Anderson
Marshall
These are some of the elite in-game coaches. Then you have the next level where you have coaches that manage NBA players, and you include Matta, Williams, Calipari, etc..
Roy Williams is not going to outcoach any of those guys I mentioned above head to head IMO.