Btw - my Koben S was delivered last Thursday. I didn't have a chance to unbox it until Saturday evening, due to travel.
Build quality seems good, though it's clear that a significant amount of the build cost went into the electric components. Disc brake rotors get some chatter on high-speed turns, but that may just be a process of breaking in.
I've put a little over a hundred miles on it so far. Range seems to be 25-50 miles depending on amount of assist. It weighs significantly more than the kickstarter indicated - around 45 pounds. Still pretty easy to pedal without assist, certainly much easier than pushing a motorcycle!
Battery pack is a 44V unit using 2600 mAh samsung cells (12s4p). It charges in about 3 hours from the wall charger, and weighs 3.04 kg / 6.7 pounds. That's 152 Wh/kg including enclosure.
I've been doing a lot more bike riding recently than motorcycling - last month I rode the Natchez Trace with some friends, ~450 miles over a week. We trained 300-500 miles per month for several months beforehand to get ready. I've learned a lot about bikes since I placed the Koben order last year, and might not do it again now. But, there's hindsight.
My commute on a road bike is about 19 minutes to go 4.7 miles. The Koben shaves about 5 minutes off that time on moderate assist .. although I'm having trouble convincing myself to use the assist to go easier rather than faster. It can actually be as fast or faster to commute by bike than on the motorcycle...