I bought a lot 40 of packs these to build the checklist. I understand why these aren't very prevalent in the hobby. The packs aren't the usual paper you would expect from a Panini sticker set. The material is more like the thin plastic used for the labels on 20oz plastic drink bottles. So it is very rubbery and doesn't tear well. Also, it has a tendancy to stick to the stickers, which often results in paper loss from the backing of the top and bottom stickers in the pack (there are 6 stickers mostly facing inwards, so the backs are usually on the outside).
I ended up sticking them in the freezer for a couple of days, and it has helped, but this is painful. I've only opened 3 packs and already have 4 damaged stickers.
