While the cookie sheets bake nicely, they rust terribly under the rims.  I have never put them in a dishwasher, but even handwashing and drying, water gets caught under the rims and it is impossible to get it completely dry.  The rust is terrible.  I have to use paper towels to dry them now so that I don't stain dish towels.  I have never had this problem with any other brand of cookie sheet.