urban decay primer potion is great i have oily eyelids and i never knew how to get my eyeshadow to last all day i used macs prep and prime and it lasted longer but still creases way 2 early then i was introduced to udpp and now i dont have the creasing eyeshadow i love it i wud never dare to put eyeshadow on with out this first personally i use it for 2 reasons wen applied under eyeshadow it allows the true color of the shadow to show up the shadow looks more vibrate and ur shadow will last u till the next day i once slept with out washing my eye makeup and i woke up and my shaod was still there...read full review »