Nothing at all ever went wrong. I replaced brake pads, discs and a chain during ownership, as with all service parts.
For a 250, it had an incredible amount of bottom-end torque, with a nice spread of power. I thought the performance and handling remarkable. I used it for work transport one winter as the traffic queues were horrendous because of bad weather. I never once had a problem with this. Wet and icy roads were just coped with. No excitement. Small enough and light enough to throw around.
Did a number of long-distance hauls, and my only comment would be that the petrol tank could have been bigger. Depending how I rode, I could get up to 135 miles to a tank, or as little as 30 (I really hate paying the extra pennies to Motorway Service Stations).
The lighting was good, with no problem on unlit country lanes.
I owned a KH250 in the late 70's. It rode great and had great pickup for a small bike. However, one difficulty was the engine design, with 3 cylinders in line, the middle cylinder didn't cool properly, and in my case, and, I understand generally, the cylinder casing cracked.
Also, as the reviewer states, the distance between fill ups was limited, by both the tank size and the relatively poor gas mileage: 3 cylinders in a 250 bike may be the cause. But, the mileage wasn't great for a small bike.