Prior to the 50 hour mark, I have run all my mowers at about 85 to 90 percent and after that at full throttle without any problems. A faster blade tip speed is going to result in a better cut or at least that has been my experience. To get a good cut at lower tip speed you need to cut your ground speed, so the faster the tip speed, the faster you can go. I like tractors as much as the next guy, but if I can cut down my time in the seat a little I am going to do it. I am too old to sit in the hot sun any longer than necessary. Now when I get in my cabbed tractor, I don't much care.