Kobe said Roy is more difficult to guard because he's so polished and has it all in his arsenal. It's the same principle as to why people think Kobe would beat LeBron in a 1-on-1 scenario. With that said, Durant's the better player. Roy is more versatile (especially with his playmaking) and polished, but it doesn't translate to him being the more effective/dominant player. Durant is a 30PPG scorer who scores at incredible efficiency, capable of putting his team on his back night-in, night-out. Roy can give you a solid 20PPG with the occasional scoring outburst, 5-6 assists, and play smart, consistent basketball...but he just doesn't have the ability to dominate games nearly as often as Durant. And besides playmaking where Roy has a big edge, Durant is the better rebounder, probably a better defender already, and it's always nice to have a 6'10'' frame with a 7'5'' wingspan at the SF spot.