I've had great results w/ whitestrips. I have really sensitive teeth so I don't get the very strongest ones (the ones I get are "premium" as opposed to "preumium ultra") and I only use one strip a day instead of two. I can't use them for more than about five days in a row w/o my teeth hurting too much. I use them a few times a month for maintenence too. People -- even my dentist -- have commented on how white my teeth are, so I'm really happy with them. The trays sound good too. As far as zoom, I'm glad you guys warned me how much it hurts -- I'll steer clear of that!