I have a couple bikes with dyno hubs and I like them. I've got a couple more Sturmey Archer dynos that I'm going to build into wheels, too. The old Dynohubs aren't as efficient as the newer ones and when you turn them by hand, you can feel the drag, but in use they're fine by me as I ride largely to burn calories anyway. The old ones aren't as powerful either, but LED lights give so much more light that they work fine. I used to turn the lights off during the day, but one time I forget and I could tell it was on just by the way that car drivers seemed to be more aware of my presence. So now, when the wheel rolls, the light glows.