</font><font color="blue" class="small">( however, I understand Exmark is the 'gold standard' )</font>
Not really. In a direct comparison side by side, I found the JD 777 to be heavier built than the Exmark by a noticable amount. Also, the Ferris and Kubota models wouldn't be considered any less quality. I don't think you will be unhappy with any of the ones you mentioned or the ones I added. I've mowed this year with new models from each. I'd actually consider the Exmark and Hustler slightly lighter made than the others. The Ferris seems to have the strongest spindles and they have suspension, the JD models have one of the strongest decks and the frame is stronger built than Exmark, and the Kubota really seemed to be a strong competitor and was the most competitively priced diesel model.
I brought most every model to my house and used them here. After all of the testing, I ended up buying another Grasshopper. /forums/images/graemlins/tongue.gif I've had one for the last 5 years and was going to add another zero turn mower. After using a front mount deck for all those years, I just couldn't go with a mid mount model. I guess that is why around here the Grasshoppers seem to be the closest to what you considered "the gold standard" by commercial operations, the highway department, and our school corporation. None of the commercial models I tried would I consider bad. Try 'em out and buy what you like. Oh yeah, I'd have to say that you are correct about not buying a residential model to mow 6 acres with each week. They are cheaper at the start, but in 10 years, you'll have as much in the residential model as you would in the commercial unit and you will have the time invested to make the repairs to keep it going that long with that much use. Good luck!