Tim Duncan -
Ewing is 4th, Mutumbo is probably better than Zo
Mutombo was a great rim defender and rebounder, but Mourning was better at every other facet of the game. The difference between them defensively was fairly small, but the difference between them offensively was a gigantic chasm in Mourning's favor.
Mutombo had a grand total of one 15+ ppg season, and that came in his rookie year. Mourning only had one season BELOW 15 ppg prior to his kidney disease. He averaged over 20 ppg prior to missing the 2002/03 season with the illness.
Mourning was a much better player than Mutombo.