On the plus side, sleeping on a satin pillow cover does help my hair from getting frizzy. But on balance, the minuses weigh out. The cover doesn't breathe so the pillow gets really hot. Plus, because it just fits a standard pillow and zips across the end, it tends to flatten the loft out of the pillow. So you have to decide -- is a lofty pillow a necessity or would you rather have a case that protects your hair. I'll continue to use the cases, but I'm a bit disappointed.