I think the difference is Davis looks to me at least to be a tough kid. Donnall was pretty soft and clearly was all over mentally. I buy into the davis hype a bit becuase his aau films always showed a physical tough player who not only was ok with contact but often iniated it.
I also though he showed really nice footwork and a soft touch. I haven't read all of the hype that people speak of so I am not sure what stands out. Hopefully he is atheltic enough to compete.