Lest I seem like a salmon, trying to swim up the waterfall ...
I don't see anything wrong with his install- indeed, it's neater than most. I certainly would have damaged the drywall more than he did, fighting with those clamps!
Sure, pigtail length is an issue- but he found it that way.
I can nit-pick ... perhaps I would have used different materials ... and I really think that steel box is supposed to have a mud ring. Compared to stuff posted here, though, these are tiny details.