As all have stated, notchiness is normal. I think Peter White does a good job of summarizing what the notchiness is and why you needn't worry about it:
Originally Posted by Peter White Cycles
Schezbzflat! My hub feels notchy!
When you hold the wheel or hub in your hand and turn the axle, you'll feel a lot of resistance. There are 26 poles and 26 magnets in the SON28 hub (fewer in the SON20). That creates 26 points around the hub shell that the axle wants to settle in, and a corresponding 26 points where the axle doesn't want to be. In the transitions between those points, the axle wants to turn in one direction or the other, to find the point where it wants to settle. As you ride, the hub turns relative to the axle, and 26 times in each rotation of the wheel, the hub wants to turn one way, and then the other, theoretically speeding you up and slowing you down, 26 times per rotation. At speed, the effects of these two forces almost completely cancel each other out, leaving you with extremely low drag overall. It's only when you don't have a lot of mass (your weight) and inertia (your speed) that the effect is to actually slow* the rotation of the hub axle. So there's no reason to be concerned about the way the axle feels when turned by hand.
Taken from
here.
*Apparently the bad word filter doesn't like the verb defined as 'delay or hold back in terms of progress, development, or accomplishment', so I've replaced it with a non-offensive synonym.
At the risk of sounding repetitive, I like the Sanyo H27. I've driven it up to 50 kph+ in a motorized testing jig and not noticed any problems with vibrations.