We had a Steiner diesel at the golf course I was mechanic at. Maybe model 420... can't remember. We also had a variety of different commercial mower types, tractors, etc. The steiner was pretty badass for difficult to mow slopes. Had a finish and a brush mower and would mow 35 degree slopes if you went up and backed down. It had the 8 tires and hydraulic push blade that graded gravel well. But not as well as a big tractor and scrape blade. I feel like the steiner will go anywhere an excavator will but you don't have the backup/safety of the boom if you get into a hairy situation. Not the easiest to get out of in a hurry but it's very unlikely to roll over. In fact, with the 8 tires, it would probably wheelie and flip backwards before it rolled over sideways. It is also pretty light so can tend to want to walk up on top of what you're pushing if the blade is floating and material builds up too much.
I will say it had low ground clearance but since the wheelbase is so short, that was rarely an issue. However, because of the low ground clearance, I did have to constantly remove grass and sticks that got pushed into the forward/backward pedal area from backing up in brush. The brush would build up inside the foot area and prevent backward pedal movement. We also had constant trouble with the belts on the finish mower. So much so that Steiner flew someone down to troubleshoot. But due to the aggressive tires and sensitive turf, we mostly used the brush mower with the Steiner and used a John Deere 2500 or Toro 3500 for groomed steep slopes.