Forbes contributors publish independent expert analyses and insights. I write about retail and the forces that are redefining shopping. L'Oréal's Colorsonic, left, and its components at right, ...

I wanted the Colorsonic to zap my grays. Instead, I got a lesson in tradeoffs. If you buy something from a Verge link, Vox Media may earn a commission. See our ethics statement. is a senior reporter ...