As far as I can tell (only talked to 2 Brammo owners) I think anyone actually riding a Brammo sticks it in 2nd or 3rd and leaves it there unless they're drag racing sportbikes. So basically the transmission ends up being dead weight and a nip on efficiency.
I can only speak to the way I ride my Empluse R. I start in 1st gear ~90% of the time, occasionally I will start in 2nd. I almost always have it in Sport mode. My accelerations are "spirited" but not wide open and I generally stay pretty close to the speed limit. I tend to let the motor rev and normally ride with the RPM between 4k and 5k so I don't shift as frequently as I do on my ICE bike and rarely use 5th or 6th gear, but I still shift quite a bit. I have tried leaving it in 2nd or 3rd and just don't enjoy it nearly as much as utilizing the transmission.
Most of my rides are short enough that range is not a concern so I make no effort to ride efficiently. My motorcycle is a toy that happens to provide transportation, but it is still a toy and I ride it as such. I am fortunate to have several beautify twisty canyon rides available without requiring me to recharge en-route as well as having public J1772 charging stations available if needed.
I test rode the 2014 Zero S and the 2014 Brammo Empluse R back to back. My preference for the Brammo was in large part the suspension, brakes, on board charger, and the transmission. I found the riding experience to be more enjoyable on the Brammo, though the performance, lower sound level, and lower maintenance of the 2015 Zero SR had some appeal. Others will have different priorities and many will choose different bikes.