RealGM

Offense: Athletic, highly-efficient rim runners who don't space the floor or carry much on-ball responsibility for their teams

Defense: Quality "modern" rim protectors who anchor the paint, disrupt passing lanes, execute switches and hold their own on the perimeter

Claxton has more talent offensively, he is just scratching the surface. He can handle the ball a bit, he can do a eurostep, he finishes in the paint from different angles... I expect him to be an all star one day. Defensively he is the best switching center I've ever seen. Robert Williams can block shots, but he is not as quick as Claxton.

Williams plays bigger and is a better post passer from what I've seen, though Claxton does indeed have more forward skills. Their defense is different stylistically, not sure how well either would adapt to different defensive schemes but both are quite effective in their current ones.