I received these baking sheets for my wedding without relly even knowing what they were. Someone picked the brand and size for me, and I am so grateful they did! I have used these hundreds of times for countless items from simple cookies to homemade fruit leather. The pans are also extremely durable. I have dropped them, traveled with them, moved them, and used them for everything and they have not warped or become disformed at all. My pans also came with lids that I really enjoy. I have made sheetcakes and other brownies with frosting that I can cover, snap the lid on, and the frosting doesn't harden while waiting to be served. Nothing really sticks to the pans, with or without nonstick spray. The mistake I made early on was that I baked chicken on one of the baking sheets and accidentally sprayed the whole baking sheet rather than just the spots where the chicken would be, so now the remaining spots are stained with nonstick spray. I have tried nearly everything to get the stains off, but I just can't remove the stains.