I have not tried the Alfine hub but I have both a SON and an SP on my bikes. Both work quite well. They keep a fairly steady beam down to about 5 mph, when they start to flicker.

For what it is worth, I also use helmet-mounted lights (Light and Motion Vis 360) and battery lights front and rear. I do that more to be sure I am seen, but I do have ample lights at night.