The Zero-S just arrived in Tucson, AZ this week. Musselman Honda is handling them- they have one in their showroom and one out at their go-kart track for demo rides.
I just got back from a test ride. I'm 6'2", 235 lbs and ride a midsize cruiser. The Zero-s is a bit small and it's a very different style for me. The bike looks great- much better in person than in pics. It has a nice, solid feel, and seems to be well-built, especially the frame. It takes off smoothly and quietly. Although the bike is quiet, it isn't completely silent- there's enough chain rattle that there's no danger of sneaking up on pedestrians like a Prius. Acceleration is a little bit flat at first, but seems to pick up between ~10 and 30 mph. Because the track is flat and doesn't have any long straightaways, it wasn't possible to test the top end or to see how it would do on hills. Braking is a little bit funky, but I think I would get used to it. It's probably due to the fact that there is little or no engine brake assist, accentuated by the fact that I'm big. Overall, this is a very fun ride- if you're interested in going electric you should definitely give it a try.