Flex-Deck (Brad) has a lot of experiece with these on John Deere 400 & 500 series tractors. He would probably be able to give the best field report on them for mowing use. But as I recall... they have treated him very well and lived extremely long lives.
How does your diesel powered DC compare with the 32 hp Generac model? I am assuming you have the 72" DC. Also, the diesel mower being heavier, does it handle differently than the 72" gas engine version? Do you get heat from the radiator right behind you? With the price of gas, I now wish I had looked into the diesel DC before I bought my 32 hp Extreme last fall. How much fuel does your diesel burn per hour. My 32 hp gas engine burns around 2.5 gal per hour.