Here is my situation: Right now I do all of my mowing with a 61" Ferris dual drive walkbehind. I bought it new in the fall, and it has the 23 hp Kawi. My only complaint with the mower is that it is SLOW. The mower cruises at about five mph on the flats, but when it hits a hill, it slows drastically. As I mowed today, I began wondering if ztr's maintain their speed on the hills. Many ztr's supposidly have a top speed of about 10 mph. Can you actually cut at that speed? Also, is anyone using the 27hp liquid cooled Lazer? Is it worth the $? Also, is anyone cutting with a 72" deck? Is it overkill? Thanks.