I had an opportunity 10 days ago to ride a Zero road bike here in NZ.
I only had an hour with it and I am very glad to have had chance to play with it.
My opinion of it surprised me.
Its nice enough, well manufactured, lightweight and easy to ride.
However a couple of things let it down. One collegue thought that its running gear actually looked too expensive for the design of the bike. Riding position was very reminiscent of a Buell (if you've ridden one then you'll know what i mean when i say you feel like you are quite forward almost over the front forks)
The ride was very easy and very very quiet with only a minor momentary sound coming from a buzz vibration at one point in the acceleration range. Otherwise no gearbox whine. and virtually no noise whatsoever.
The bike is quite small and quite light. and i'm thinking its about 60% of the weight of a vectrix.
However the only thing that killed it personally for me was its lack of torque. Possibly not a real lack of torque - possibly a percieved lack of torque. But then i think its 50% down on electric motor power and 66% down on pack voltage in comparison to a Vectrix. However the top speed of the Zero is higher than the Vectrix oh and the zero doesnt have regen at all. I can't remember if it was an AC or DC motor but in effect it could well have been DC.
So..... even though the Vectrix is considerably heavier than the Zero, it certainly has more torque which is important when riding and riding a bike low on torque is certainly less fun.
My overall opinion on the zero... yep nice but put the vectrix pack/voltage/motor on it and there would be a winner !
At $15,995 its almost as expensive to a 2012 Harley-Davidson 1200c Sportster Custom in this country (883 is $14,495 and 1200c is $17,250)
Its a hard sell I think.