What is a defines "the best defensive player?"
Shotblocker? I think he and Hayward are probably the best shotblockers on the team. Millsap has the best hands/steals. I think Favors shows the potential to be a good defensive player... But he's not there yet. HE goes for fakes, is often times outmuscled down low, and his P&R defense leaves a lot to be desired. He's long and athletic... That's about it.
IMO, Hayward is our best defender. He can block from the weak side, stay in front with his lateral quickness, stays down on fakes, and can defend a variety of positions from PGs to SFs.
As far as all around fundamental and physical defense? I think Kanter is head and shoulders above Favors and every of our other post defenders.
He keeps guys out of the paint, bodies them up, boxes out, doesn't go for fakes, draws chargers, and best of all, HEDGES ON THE PICK AND ROLL!
He was getting beaten by Aldrich because every time he touched Aldrich he got a foul called on him. Rookies never get the benefit of the doubt.
Best Jazz defender? Hayward
Best post defender? Gotta go with Kanter