Guess I've been lucky. I've had a glass top now for 5 years and the only skillets I have are cast iron. Haven't had any problems. I also use my water canner/pressure canner on it without problems. Never even occurred to me that I shouldn't do it. This is the first time I've ever had an electric stove and I really miss the gas. The glass looks nice, but I probably wouldn't be what I would pick if I had a choice.