I had these Calphalon baking sheets for years until I recently switched to some from Williams Sonoma. They performed admirably the entire time I had them. These are very large and so are very good when I'm baking large batches of cookies. I can usually fit from 18 to 20 cookies on a sheet. If it's a cookie that does not spread I can get 30 on a sheet. This is a huge bonus when you have a lot of baking to do. The sheets heat evenly and the cookies bake nicely with gently browned bottoms. I've only very rarely had a batch get too dark on the bottoms. I can't speak to the non-stick qualities of these as I always bake on parchment paper on these for ease of cleanup. I had these pans for at least five years and never experienced any sort of warping or any issues, despite baking at temperatures up to 450 degrees. I definitely recommend these for those who do a lot of cookie baking. They are easy to use and stack nicely.
Vernon Rockville, CT