I have a Cygolite Rover II. Happy with it. At a reported 255 lumens, fine for normal commuter speed. If going very fast (downhill or tailwind) would be more comforable with a brighter light. Seems tough & rugged. Homebuilt a spare battery pack from 4-AA NiMHs. This has enough power to run it for about two hours.

http://www.amazon.com/CygoLite-Rover.../dp/B001P9H0ZS

Bought the Rover II when the Magicshine was new. The Magicshine was reported to have sloppy build quality & questionable longevity. It may have improved since those reports on the early units.