At the S.F, version of National Hydrogen and Fuel Cell Day yesterday, got to test ride three pedelecs, provided by the New Wheel electric bike shop of San Francisco: http://newwheel.net/. Sadly, all rides were restricted to the flat parking lot at Pier 27, so I wasn't able to try out the assist anywhere I really needed it, despite San Francisco's hills staring at me just across the Embarcadero.
The three models on hand were the Gazelle Arroyo C8 (actually the bike they had there was labeled 'Orange C7', but they appear to be similar); A Haibike model, I believe the Enduro Cross SM; and a Stromer ST2. The Gazelle was in essence a Dutch comfort bike with electric assist added - step through frame, upright seating position, covered chain, serious rear rack, etc. Frankly, I couldn't see the point. On flat roads who needs assist, unless you're constantly riding in strong headwinds? To me, 'pedelec' and 'leisure' just don't go together, unless it's a cargo bike. The battery is located below the rear rack, and designed to be easily removed and carried (built-in handle). The motor control was on the left (I'd prefer right), but well sized and shaped for thumb use without looking.
The Stromer was at the opposite end of the spectrum. Calling it an e-bike is sort of like saying that a Panamera S e-hybrid is a PHEV. Riding it with no assistance was an effort, as it's built halfway to a motorcycle, and I wouldn't want to carry it up stairs even with the battery removed. I found that it had by far the most power and torque of the three, and with assist at max. it often felt like the bike was running away from you, it's accel was that fast - unlike the other two, which are limited to assist below about 16 or 18 mph, the Stromer keeps helping up to 28 mph. From a standing start I was able to accelerate to just over 29 mph in what I'd estimate was less than 50 yards. I'd never want to use max. assist on this bike in traffic. '1' was fine, and '2' was reasonably controllable, but '3' was a matter of gangway! for anyone who hadn't just been riding a motorcycle.
I made sure to warn the people who followed me in riding it not to put it to max. right off the bat, because it just doesn't feel like a bike. But all of us (the guys, anyway) came back from our rides with stupid grins on our faces (if somewhat abashed), expressing some variety of 'whoa!, this ain't your mom's bike!' I wouldn't want to ride it maxed out except on a open road with near zero traffic. I'm also under the impression that you might need to license this, as I thought the law was anything with motor assist over 18 mph counted as a moped. [Edit. They changed the law here last year, and I missed it: http://www.peopleforbikes.org/blog/entry/new-e-bike-law-passes-in-california]
Price is high, as you'd expect: $6,990. The battery is locked inside a frame compartment with a cover, so I didn't get to check it out; I see it's credited with 814Wh and up to 90 miles of range. The motor control is on the right, well placed for and sized for thumb use, and there's an LCD display of speed, range, battery state, power setting etc. on top of the top tube.
The Haibike seemed the best compromise to me, light enough to ride without assist much of the time and get a good workout (and maybe even carry up a flight of stairs) or do a fast commute, not excessively powered but able to cruise around 20 mph with reasonable effort and full control. I have no need for a suspension on a street bike, so I'd prefer it without that to save money and weight. The battery is attached and locked to the down tube and has a handle, so is as easy to get to and remove as the Gazelle. The only thing I thought could be improved was to move the motor control/display from the left to the right side, putting all the shifting etc. over there, and it was perhaps the control that looked the most like an add-on instead of an integral part of the bike. Worked fine, though.
It occurs to me that widespread use of pedelecs would lead to cyclists being more willing to obey stop signs and red lights, instead of cruising through them whenever it's clear (and often when it isn't, to driver's fury). We're trying to conserve energy by not having to accelerate from a standstill, but with the motor to assist you, it's no big deal. In my case, I'll stick to a bike powered by myself as long as I can, as I ride for exercise as much as for transportation, and it's far too tempting to succumb to the siren song of minimal effort hill climbing. But if I had to commute in a city like S.F. over those hills on a daily basis, I could definitely see this as a great option.