I bought one of these kits from VO and am enjoying the fact that the light is always at hand. I do have a problem with the mounting of the headlamp: Since I have full fenders, when it is mounted at the fork crown, the light gets impeded by the front fender. I guess I'll look at mounting it lower down on the fork. I'll need a new mount for that.
The main question I have is about drag. I used to have a bottle dynamo several decades ago, and I don't remember it having anything near the drag that this one has. On the stand it stops the wheel in just about 1 revolution from a decent speed (not scientific, I know). I thought this would be better with me on the bike (momentum is a great thing), however it still feels like I have a brake on. I tried adlusting the amount of contact with the tyre, but the friction is either too low - and the lights do not function, or too high and the drag is like an anchor.
Don't get me wrong; I was expecting some drag, but this is waaaayyyy too much. I hope I'm doing something wrong and that there's something you guys can suggest to make it work better.