The samples are all top quality, but it is somewhat difficult to really know since it is a small piece glued to card stock, they did away with the flip books a while ago (so says the site). Their prices are pretty much in line with all the highest quality goods I could find elsewhere on the web (except ebay and then you never know what you are getting). I've purchased some really nice scraps on ebay, and some not so nice pieces for recovering cameras, so I wouldn't completely rule that out as a source of decent quality leather.
The Hewitt stuff is more expensive because of the cost of importing it, and it is supposed to be some of the best stuff. I think they only import the top grade from Hewitt and then they say they inspect each hide to make sure it is of the highest quality.
They did ship my samples really fast.
The only thing about the composite leather that I didn't like is that it had a kind of slippery feel to it. Since I was shopping for leather to cover a TLR, I decided slippery was a bad thing. Ended up buying many different scraps and samples on ebay until I ended up with a nice thin piece of black goatskin that is waiting for me to restore an original model Rollieflex TLR (second year of production I think). If you have never covered a camera in the nice soft garment leathers, you don't know what nice is. Compared to the hard thin cold leather on most cameras, it's soft and warm and gives you a great grip without straining your muscles. I have a Yashica 635 in a somewhat too thick red sheepskin, but it is so soft to hold now, much nicer than the stock leather. Anyway back to the composite stuff, it is stiff enough that it would probably make a really nice folded bellows, though the corners might be a little difficult. Artificial leather (Pleather) might be better for a bellows.
One of these days I need to buy a couple of books on book binding/making to add to my knowledge. Though I did recently make a perfect bound book of a user manual for a piece of equipment. it was a half letter sized of about 200 pages, and I was sitting looking at the pile of pages and thinking. Had some PVA on hand for another project and a bunch of clamps... Seems to have turned out OK for the number of times I've tried this (being number 1).
I forget how far away Gloversville is from me, I'm thinking not to far to the North, but I can't really remember.