Stainless steel grids are very good and durable. They are highly resistant to rust, and are also the most expensive blisters. The longest life, the best heat retention, there are assessments for this type of blister. Next is porcelain-coated cast iron grates, which is the next best thing to stainless steel. It keeps heat well, with a long life. However, it does eventually rust when the porcelain chips is still covered, but be assured that it takes a few years for that to happen. Finally, porcelain coated steel grids, which look pretty cool, but are prone to chipping and this leads to rust, and this gris is rated for lower heat retention than the other two.