Great video Glenn. I thought the main differences where purely technical in this case. Who made noises when they position shift, who bent strings with the left hand when they probably shouldn't have. This in itself leads to a different sound, which in itself can work for or against the players own voice. All of these can be worked on if desired.
I think the whole "tone from the hands" is much deeper than that. I come from a classical background and we've done this experiment with some of the best players in the world sitting side by side swapping the same instrument. These players have as close to no technical flaws as you'll get and the results are pretty interesting. Their philosophy of playing, how they approach tone production, what is the sound that they want to make, starts to shine through. There's even a huge difference where geographically someone was trained. When we try to take these things away and be generic, ask them to try to sound the same as each other, a lot of their character is lost. I'm certain there's a bit of this going on in this video. When a good player makes sound on any instrument they impart some of themselves on that sound. It makes an experiment like this difficult.
All of this is subjective of course. It's not up to me to decide what's a good sound in the end. Only the listener can decide for himself.