IME slopes are hard on lower cost hydrostatic drives and drive belts. (duh) I had a Simplicity residential rider and then got a Cub Cadet shaft drive. The shaft drive cubs hold up well on yards that aren't level but I found the deck wouldn't raise high enough in hot dry spells here. I bought a Kubota GR2020 4x4 mower last year and love it. Zero turns are dangerous on steep slopes unless you can mow straight up and down and pivot at the top and bottom.
