I took a ride with it helmet mounted the other night, and definitely took a route that I would not have previously felt comfortable riding in the dark. People changed their minds about left turns, or pulling out of parking spaces when the spot hit their mirrors or windows.
Also, the folks jogging on the path around Prospect Park moved over onto the grass as if a car was coming. I kept a blinkie on the handlebar just for good measure if I was looking in a different direction. It's so worth it, as long as I don't have to tell anyone who doesn't ride how much it costs
