I was going to mention Fil; he does some very interesting analyses of all genres. He recently did one of Lisa Kudrow and Lady Gaga performing “Smelly Cat” on the Friends Reunion show. He said, basically, “I suspect that the person who suggested this did it as a joke, but I’m going to do it anyway.” And by golly if he didn’t bring a lot of insight into the different fingering techniques that the two of them used.
He’s a bit different than most of these types of reactors, in that he’s not even pretending that he’s watching the video or hearing the song for the first time. On the contrary, he’s obviously done some research for each one, and as a professional musician I’m sure he’s already familiar with a lot of the artists he’s covering. But I do enjoy him.