We are looking to buy a new range. So far, we like the gas, double oven, 5 burner Kitchenaid. I'm a little concerned that the online manual says that the porcelain can develop hairline cracks when self-cleaning. I assume the ovens are lined with a porcelain coating. The Whirlpool model says the same. Just wondering if anyone has any experience with this or this range in general. Thanks!