I'm happy with my ZF9 DS, I have 11000 miles, and I'm waiting on a new motor as I've been dealing with intermittent glitches for a couple of years now. My bike recovers from the glitches on its own very quickly. Zero believes the glitch's are due to slop in the motor bearing. I live on a dirt road also so Zero blames the dirt and dust. I've had problems with the plastic breaking almost everywhere, the rear directional mounting locations have broken out twice now, I'm customizing the rear fender, making it smaller and smaller as I relocate the directional lamps. Zero has been good with warranty work, I had a dealer 40 miles away but they are no longer a dealer for Zero because of delays in warranty work compensation and poor sales. I had an employee of zero come to my home for the software update once since then. I charge my bike from my Off Grid home solar system primarily. The bike has never left me stranded and it runs great most of the time on my 60 mile round trip commute. the furthest I've gone on a single charge has been 80 miles. My rear tires only last 3500 miles or so.
Carl