I have never made that comparison. I have only used Insul-Bright.

I have bought some insul bright but haven't used it (or mylar) yet. For the record, I have used about 4-5 layers of cotton batting and it was as good as any pot holder I've bought at a store.

I haven't tried the insulbright. I have used cotton batting several layers, also cut up an old silver cover off an ironing board that had seen better days. Used that in my layers of cotton batt. Worked Just fine.

jacke