your right about bogging but that only comes to play in high grass. The pumps dictate speed otherwise.
I run a 60 29 kaw, 52 27 koh and a 52 22 koh.
I wouldnt compare it to a yard. I'm comparing to the 24 acre campground I cut, thats pretty much wide open besides the dirt roads. We were lucky to get out of there in 5 hours.
The campground owned a 48" lazer and a 60" cub that was broken at the time. They were paying for the simple reason it took them days to cut and trim the place. If they could cut that place in a reasonable time they wouldnt pay me $2700 a cut.