Which over-the-counter teeth whitening products really work?

I have tried many of the products and have founf Dr. Georges to work the best and it is one of the cheapest and can be purchased at any walgreens.

Which over-the-counter teeth whitening products really work?
I read in an article that people can get a more higher concentration formula from their dentist...specifically of the product Crest White Strips....SO...I would say that one in specific. BUT then again I've always heard Rembrandt worked well too. I need to use them..I smoke WOOT.