Cooling
Winner: Purple HarmonyPurple RestorePremier's GelFlex Grid pillow runs 5-8°F cooler than Coop's shredded memory foam. Independent thermal imaging (RTINGS, Sleep Foundation) confirms this. The grid pattern vents heat that any solid or shredded foam can't.
Coop uses a breathable knit cover which helps but doesn't match the grid's ventilation. If you sleep hot and pillows are part of the problem, Purple is the clear pick.