In alot of areas E-bikes are illegal. They are considered motorized (electric is a motor), but don't carry a license. As motorized they can't be on the sidewalk, and since they don't have what is needed to be street legal (on most) they can't get licensed for street use. Our local stores have had trouble with the darn things, as the major retailers distributors send them, but they can't be used here.
Fortunately with the weakening of the Big 3 Auto companies here they were not able to throw out roadblocks on legalizing them like they did mopeds back in the 1970s. Mopeds are effectively non existent here due to the licensing and insurance issues, you might as well go "whole hog" and buy a motorcycle.
Here so long as they are "equipped with" pedals they fall under modified bicycle laws. What the "equipped with" means needs to be fought out in the courts or clarified by the legislature though. A car for example is considered to be equipped with a spare tire even though it is in the trunk and not installed. The police are interpreting it an installed in a usable position as far as E-Bikes are concerned here.
I've read up a lot of the debates online. One of the sillier claims was about Chinas large increase in accidents as the number of E-Bikes went up. The raw accident numbers
were a major increase. What made it silly was the accident increase for the bikes was substantially lower than the increase in the number of bikes (more of the bikes meant a lower accident rate/1000 bikes).
Here there was a 3 year trial program as the government tried to find a justification to restrict them. The trial showed them to be safe (the trial ended in late 2009). Even over the near year that I have had them the number on the road has increased substantially and drivers have learned to treat us better (hit an E-Bike and it WILL damage your car). Riders tend to be older (minimum 16) which translates to more common sense. A lot also seem to be 30+ with actual driving experience resulting in better cyclists as well. I did have one near miss recently as a car (older lady) pulled up beside me and made a right turn just as we got to an intersection, I had to slow hard and turn inside her to keep from hitting her.
The big issue with them is the batteries. Very heavy (lead acid) which means too much power goes to moving the batteries and too little to moving you. Some Lithium ones have begun to show up but the price is high (added $800 to one that I have seen). Unfortunately there are patents on making larger NiMH so they are out (patent owner controlled by Big Oil apparently and they fail to sell larger batteries - even when they have a contract to do so apparently.)