Ah yes the old hill and the two skid mark syndrome. One down the hill and the other in the shorts! A friend brought over a brand new big commercial ZT claiming it would cut my steep hills around the house, same thing, back on the trailer it went! lol
When you find something that can overcome a potentially dangerous job, and then something fails or is over looked, you can find yourself in a dangerous situation in seconds!
I routinely cut my steep hills with the Steiner. No problem. Last year, I forgot to have the deck in float position, so when it went over the edge of the hill, the back end came up and because the steering mechanism probably can't cope with very large loads, the machine jack knifed. It was very quick thinking, jamming the thing into float, and straightening it out that probably averted an accident.
It's why I keep repeating, as far as who operates equipment. It's not when things go smoothly that matters, it's how things are handled when things go awry that can matter the most.