I just returned from a 75-mile ride with Bill (Sunnysideup). Me on my 2012 Zero S and Bill on his 2013 Empulse R. We traveled from my home in Pacifica, north and east to Sharps Park Road, then south along I-280 at 60 mph, turned off on to Highway 35, picked up Canada Road to Woodside, rode up Woodside Road (Highway 84) to Alice's Restaurant, where we had lunch and we both recharged our batteries for 90 minutes. We then rode north, up Skyline Boulevard, then down Tunitas Creek Road, up Irish Ridge Road to Verdi Road, to Pursima Creek Road, then Higgins Pursima Road to Half Moon Bay, where we headed north back towards Pacifica - but Bill didn't quite make it. When we got to Montara, he decided that he wasn't going to make it the 8 miles to Pacifica, as he only had about 15% battery capacity left (I was showing 4 bars at the time). So we went round and round in Montara looking for someplace to charge up his bike. We first went to the Sheriff's station, but no one was home. Visiting a nearby county park did no good as they had no power at all. Bill tried to get power from a local Chevron station, but they didn't care much for electric motorcycles and told him to get lost. We finally ended up at a Mexican restaurant a block away. They were very accommodating and let Bill charge up at their outbuilding.
I rode Bill's Empulse along Irish Ridge Road and I liked the Empulse's ride and handling. I thought the transmission shifted smoothly, both up and down, and I didn't find the slight "clunk" when taking off from a stop very noticeable. The only thing that I found irritating was the abrupt throttle response in first gear and second gears, between on and off throttle. It reminded me of many IC FI motorcycles. Most likely this was the result of little flywheel effect, a fast power take-up on the throttle and slack in the drive-train. I think this can be worked out with further development. In the meantime, keeping the chain at its tightest recommended slack should minimize the "lurch". Frankly, I am not at all sure why 5th and 6th gears are needed. I doubt I would use either of these gears while keeping to the posted speed limits. I think 4 speeds would work just fine to accommodate the Empulse's performance envelope.
I believe the real issue with the transmission is that it is not as efficient as a rubber-belt direct drive. As you know, my Zero has less battery capacity than the Empulse. We both rode the same distance, at the same speed and charged up for the same amount of time, using the 120V outlets at Alice's. Granted, Bill had to travel 12 miles to get to my house, but he came up short in Montara and I was able to continue home and upon arriving I just hit the final two (flashing) "bars" on my "fuel" gauge. So my estimate is that my Zero is about 15% more efficient at speeds under 60 mph (we didn't ride faster than that) than is the Empulse, especially when you consider the Zero's slightly smaller battery pack. I should mention that when we hit the coast, we were bucking winds of around 40 mph and the temperature was in the 40's. Not the best day to go pleasure riding on an electric motorcycle.
So I think our speculation regarding transmissions vs direct-drive is pretty much borne out by this one sample comparison ride. The transmission is the thing to have if you want good acceleration and pulling ability, but direct-drive is what you want if you just want to roll as far as possible. If anyone else would like to perform a similar experiment, go right ahead. Oh yes. You can hear the Empulse coming from some distance away. It makes quite a whine, compared with my Zero.