Here are some comments from Reddit owners:
2016 DSR. "I drive the bike daily for commute, about 100km/day and have it since sept 2016. Real range is about 110-130 km @ 100km/h and a lot more going slower. Didn't lose a mentionable amount of charge in all the years of ownership, maybe 2% or something. Odo is at 60.000km's now."
"I have a 2016 SR. Bought it 2 years ago with 27k miles and it’s at 32k now. The onboard charger died a few months ago. The previous owner didn’t mention getting a new charger so I presume it was the original.
Also, It will act up if left out when it’s really rainy for several days. Will refuse to start until it dries out which can take a couple of days. So based on my experience use a cover if it rains alot (unless you have covered parking) and budget for a possible charger replacement. Other than that it’s been a great bike. Battery is maybe 80% capacity compared to new? Hard to tell. I get about 60miles of range with mixed highway/city riding and I ride it hard."
"I had a 2015 S that had the controller fail the day after delivery and then the next year the charger died."
"I have a 2014 SR with 5,000+ miles and the bike is still going strong with the exception of a failing onboard 110v charger. It was purchased for $6K USD with an additional external charger and luggage included."
DSR BlackForest. "Motor: no moving parts other than the axis; good for a million km at least.
Battery: mine (DSR 14.4) is from 2018 with 26000 km and still no discernible drop in range.
Controllers: i can’t say, but from what I understand they are also relatively generic, so there’s a good chance of fixing or finding replacements.
DC/DC converter: this one is special. It will probably fail sooner or later, because Zero decided to use one that is not made for input voltages their battery supplies, but is replaceable with a better one for a few 100€ (cheaper than the OEM)
Charger(s): I cannot say. Mine are both fine and there is a relatively large after market offering."