I am shopping for equipment for the 2011 season and am taking a serious look at Toro. The two pieces I am interested in are the Grandstand 18HP Kawasaki 36" Deck and the Z500 Zero Turn 27 HP Kohler w/72" Deck. My main question is regarding the 'acres per hour' rating supplied by Toro. The Grandstand is rated at 2.9 acres/hour and the Z500 is rated at 6.2 acres/hour. I realize that these ratings are in ideal cutting conditions and are likely unrealistic under normal conditions. I'd like feedback from others who have used these machines (or other Toro machines). What kind of acres/hour numbers have you normally experienced?