I use to love the NuVinci when it first came out, fine tune the gear so you ride at the exact cadence you want, but so many of them have a misaligned gearing where it doesn't have any over-drive, I just don't want to keep going back to the original docking station (so I don't have to wait 2 min) to swap for another NuVinci, hoping it's a good one. I pretty much only get bikes with the S/A shifter, whose only issue is once in a while, a misaligned one has its gears skip if I don't apply pressure throughout the whole pedal stroke..and the most dangerous part is when I get off the saddle on a hill and the gear skips and my foot drops as if a chain just snapped.

I've had the drum brake not release after pulling the brake lever. Most times, I would push back the brake arm by the drum and it the wheel will spin easier.