I have been using these for years and have thought them to be excellent. That said I ran into a situation last week in which a handful of them were such that you could not insert an 8.5"x11" paper in them with curling the page (would not lay flat) and I found it necessary to trim about .25" from the 8.5" side to make it fit. Very odd.
Last year I had purchase a box of 100 3mil protectors last and the quality was perfect. The sheets were made of high grade CLEAR plastic and wrinkle free. I just bought another box of the same item and was totally dissatisfied so I returned it. The sheets were cloudy made from lower grade of material and the were not flat but wavy. Thumbs Down.