I used one of those Dixon mowers for many, many years. I don’t have any hills or cliffs, but that thing would lose control quite often because a chain can easily pop off. If I was on a slight grade, I was going for a ride. Those things can be deadly on hills. The tires also tend to spin easily on just a bit of moisture and they lose steering on one side when the tire is spinning. I would never trust one on anything other than perfectly level, dry ground.