Ok, were looking to purchase a new mower; something like a 60" rider. I have literature from about every company that sells within my area, and I have gone and looked at about everything there is to look at. Regardless of what the salespeople say, i want your opinions. Which is better, a gas or diesel powerplant? The mowing covers all types of terrain; flat open ground, hills, rocky/rutted out yards, etc... assuming that the hp is relatively the same which would you recommend and why???