I have regularly used Crest Whitestrips for the past few years now while giving the cold shoulder to other newer teeth whitening products. Why? I'm not so sure. I think because I actually see a difference using Crest Whitestrips. In fact the only downfall I find with this product is that I tend to have whiter upper teeth than lower teeth. The strip just won't stay put! I don't talk, laugh, smile, curse at anyone, perform personal monologues, nor even recite popular quotes from Spaceballs while I am wearing these strips, but the bottom strip invariably ends up halfway down my throat… read full review »