An early model years ago was able to tip over and keep running before it was recalled ... not the kind of thing you want sitting out on your lawn or the sidewalk.
Been running this mower for 5 summers now and little to no issues. Blades need to be changed every 2-3 months depending on conditions. Overall it has saved me probably hundreds of hours on manual mowing.
If your yard has any relatively steep parts, they fail. I was 100% ready to buy one, only to discover I would still be mowing 30-40% of my yard by hand. I suspect there's a reason most of the demos are on completely flat yards.
I'm not aware of really anything capable intended for homeowners besides a good ol' push mower.
Being tracked only really solves the traction part of the equation so they aren't necessarily any better at navigating slopes safely than a wheeled mower.
I thought the same thing about tracks: only solves the issue of traction/ground pressure, but for whatever reason they're supposed to be better on slopes.
My (wheeled) mower sometimes slips or gets stuck on a particular area on my property because I often don't have enough traction to mow up & down the slope if the ground is not extremely dry: grass is enough to cause slip. And sidehilling causes the upper wheels to lose traction. Perhaps the increased "bite" of the treads compensates for this? Dunno.