i did britesmile a few years ago, and then zoom this past year. i also got professional trays that i do for maintenance. i like the trays alot more. both dental office visits hurt like hell. who needs their teeth to be white "in just one hour" if you really think about it? i think dentists only do it to make alot more money. the trays are just as, or more effective, but don't cause you such extreme pain.