Al's brilliant low-post skills are one of a kind, and Sully is just a more regular undersized big, albeit both have incredible instincts in their own ways. I think looking back at the early days of Al, he was similarly a bit overweight, which was why those bad sprains of his kept him out of the line-up for prolonged stretches. I think in this quicker era of the NBA I'm happy to keep Sully, it was Al's suspect D that made him expendable in a lot of people's eyes, though GM's and fans alike are always astonished by his seemingly unlimited repertoire of post moves.