I have a dyno-hub on my bicycle. A couple of days a go, as an experiment, I also put on a cheap cree magic shine clone.

There simply is no comparison, the cheap (about $15 for the light and another $5 for the defusing lens) worked better in all ways. I suppose that if I had a three or four hour commute I would have to worry about the batteries giving out; but with my 15-20 minute commute that is not a concern.

The cheap light had a good cutoff (with the defuser lens), and unlike the dyno light, it filled all of the lighted area. The light was significantly stronger and wider. Even on the "low" setting the cheap light was strong enough that the effect of the dyno light could not be seen.

The dyno light has a place. as a permanent part of the bike it serves as a "minimum legal requirement" light for when I forget the good/cheap light; but, as far as quality, as a headlight, there is just no comparison. Save a coupe hundred dollars, get the cheap one