So I know this is an oldish thread but I wanted to post a quick update. I've been commuting on average twice a week with this light, occasionally with another, non-dynamo hubbed bike, and can say that hands down a dynamo light is the best investment a serious to semi-serious commuter or transport cyclist can make, hands down. My morning commute is early (3-4am early!) so it is always dark. The IQ-SX puts out plenty of light for my half suburban / half rural 17.5 mile commute, but the beam spread is not super wide, so I miss a bit of what's on the side of the road. No worries for me because at that hour I may only see 3 cars on my ride in, so I usually just ride right down the middle of the road. When I ride my other non dynamo lighted bike I pine for my dynamo, even though the battery light puts out what appears to my eyes to be brighter light. With the dynamo I don't have to think about any lighting requirements at all; its just there and it works always for as long as the bike is moving forward. None of the mental games like how long before the battery dies? or where on earth am I going to carry the battery? (mine is a separate battery/light style) or did I remember to charge the battery? or do I need to get a new battery because my old one is near the end of its service life? Battery this, battery that, blah blah blah. So if you're on the fence about whether or not to take the plunge, I say DO IT! You absolutely will not regret it!