I've had a dynamo light for 5 years now and would never go back. I took that bike last night into the darkest part of the city that I know, a completely unlit portion of Prospect Park and the Cyo Premium throws a beam that lights the road in front of you better than the streetlights in the rest of the park. There was a cop car where I went into the dark and I thought he would warn me not to go there.
Probably the biggest users of dynamo lights these days is Citibike. Every one of them has a dynamo. I'm surprised that this didn't create an increase in demand in bikes for sale with them built in.