yup, i say crest whitestrips too. however, in the first couple days i started the strips, i developed a scratchy, sore throat.. same with my boyfriend. this was probably because we tried not to swallow the gel and our throats became dry. i didn't experience any tooth/gum sensitivity, but then i don't think any part of me is really sensitive physically. little parts of my gums did turn white after getting in contact with the gel tho.. and it stung a little but, as weird as it sounds, i enjoy pain in my gums. lol i dunno.
it just depends on the person.. some people can use the strips with no pain, little pain, or pain to the point where they can't even finish the week or 2.. i say give it a try. not too expensive but its nice when you find them on sale. i need to buy more tho cuz my teeth are starting to yellow again..