I need a new Exmark Lazer Z. But I have been given a price of $8500 for the Exmark Lazer AS with the 60" Ultracut deck and 28 hp Kawasaki. Is this a commercial mower, it goes 1/2 mph slower than the Z and weighs about 200lbs less? I need to know if it climbs up an down hills as well as the Lazer Z I own. Is it dependable ?