I haven't had it done professionally, but I have had good results at home with gel and the molded trays. It's amazing how you look at people who HAVEN'T whitened their teeth and think how yellow their teeth look. Recently I read that the contact with the peroxide on the gums and oral mucosa may lead to oral cancers at a younger age. It said that professional whitening was less dangerous because the peroxide came in contact with the gums less often since the trays fit better. What doesn't cause cancer anymore? I say go for the white teeth.