Like BBF says, it's really not that big of a deal. The time is closer to ~14 mins compared to 10. This also doesn't include mounting and cutting/inspecting as mentioned. I think actual time would be pushing more towards 16-18 mins, which isn't a crazy fast time by any means. (Not that I advocate speed stringing unless necessary). The machine is not the ESII+, maybe the older ES machine. The screw type clamps were on older Gamma machines. He unclamps WAY too fast, the tensioner on those things is really slow (to pull to reference).
I am pretty certain that the string is not completely done tensioning when he unclamps. If he's using something that pulls THAT fast, I'd be impressed
He uses a double half hitch for a starting knot, which in my book is a no no. His fanning technique is sub-par. Just because you "U" bend the string doesn't mean you're preventing burns.
You actually need to MOVE the string back and forth to make any difference. (He is inconsistent about this). He could also string one ahead to reduce the wear on the strings as he weaves, but this isn't a deal killer for me. His final cross YANK was a little too harsh for me as well. As a major nitpick: when he pulls his knot, he gets a little too close to the frame on the first pull. If the string were to snap, he'd have very little string to work with (fix).