I agree with Razor -- I had more cons than pros with mine. They didn't transition very fast, they didn't get very dark, and driving at night was a pain as oncoming headlights caused them to darken - which was ok while there was oncoming traffic - but once the headlights are gone you're driving with a pair of sunglasses on in the dark. I bought a pair of prescription sunglasses and while its a pain to have to carry them around - it worked best for me.