FSM,
Nelbuts is correct. The F-935 can mow at 10 mph if the conditions are right, i.e. wide open area, fairly smooth ground, few trees, etc.
The tractor lugs will indeed tear up the turf. I used to have the smoother turf tires on, but I was spinning out a lot on hills. The lugs solved that problem. I only use this on large commercial accounts and acreages/estates.
The ride is very comfortable. I have a Grammer seat that has it's own single shock suspension. You just dial in your weight and sit down. I have to admit though, that after 8-10 hours of mowing, there still is a little bit of a** fatigue.
The bad thing about mowing after dark is the amount of bugs those lights attract. Then the bats start dive bombing in front of you to eat the bugs.