I've been using a Fenix LD20 for over 2 years commuting. When I got a Magicshine last September, I moved the Fenix to my helmet. It served well as my primary light, and is fantastic as a helmet light. It weighs next to nothing and holds a charge well on AA rechargeables. I don't run mine on the turbo mode but the second-highest setting and can usually get a week of commuting on one charge. Several times my Magicshine battery has lost its charge during a commute, and the Fenix has bailed me out. It also is very easy to carry a couple spare AA batteries in case the Fenix goes dead. My only complaint is the lack of a low-battery indicator light. When its batteries get low, it fades very quickly.