It's cool, but seems like one of those times where the sketch is one of legend and the reality doesn't measure up to the fantasy.
I've wondered that about certain "holy grail" clips. Back when Henson #1 was unavailable to us, I had wondered if that one wouldn't be that great, but it turned out to be one of my top five favorite "baker films". And when I finally saw the original People in Your Neighborhood (with a postman and fireman) it turned out great. But on the other hand, the formerly rare "Seven Monsters" (though I don't know if that was a big holy grail to us, though it was to me) and "Cracks" are just okay for the most part. But I feel like this particular segment is amazing. The colorful diamonds was something I wasn't expecting (previously there had been a black and white image for this segment, which didn't have it... In fact, I didn't realize this segment used a black background instead of the usual first season beige background). It's probably more simple than I'm thinking, but I'm sure it's something Jim was proud of.
Considering that it's a unlisted video, and going to the user's main page gets a blank account, that would take some serious sleuthing to gather what else that member has, if any. Considering the secrecy of the account and video upload, it makes you wonder how this person even got it in the first place. And in good quality too.
I wonder if it might be the same person who obtained the rare "Cracks" segment. Or maybe an archivist at Sesame Workshop. I doubt it's Ryan from Tough Pigs though I know he does work for Sesame Workshop. I had wondered if maybe it was Michael Davis, since in the sources section of Street Gang he says that Sesame Workshop made him DVD copies of the first five episodes (this segment appeared in episode 3). But we might never know.
Of course, considering it's unlisted, I wonder how it was found out about. I found out about this being online after seeing it shared on both the Muppet Wiki and Tough Pigs facebook pages. I wonder why it had to be unlisted anyway... It's not like Sesame Street clips normally get taken down (unless maybe the clip appeared in the 20th anniversary special, or if it's a full episode).