I honestly don't know if he is the best coach. Spurs are the smartest team in the league, no question even. But, he coaches the smartest PF in history in my opinion and a few other veteran, smart players. He is a good coach, but I think that there are many other coaches that are a bit better, a bit worse, it's hard to call. D'Antoni on his way to bring to live second team in row after doing it in Phoenix as well. Yeah, he got his ass kick by Pop, but he played something now to this league or relatevily now, doesn't that count? Let's see Pop take the Sixers and take a ring with them. I think that you must prove yourself in at least two teams before you can be called the best.
He is in the right franchise for him and it is important as well. From current managers, I rate highly Pop, Sloann, D'Antoni, Jackson (sorry, Doc, no place for you on my lyst).