O.K. Doyles here we go. I purchased a Ferris IS3100zp 61" 32hp., back in July. I bought it because of where I am located. Gas here is $6.00 U.S/gallon propane is; $2.00 U.S/gallon. That is why I wanted to go propane over gas. The tanks hold 7+ gallons of propane each. I can work for about 10hours on that. I have had problems. I dont believe it is fair to compare my gas unit to this one being that its a different brand, and less h.p. I have had to change out two mixers on my unit, that were faulty and am supposed to get a new one from enviroguard who makes them and the propane parts of the mower. I still have not recieved the new mixer. I live out of the country and have no dealers here. My dealer in the states is awesome, and so is ferris, for taking care of every problem i have had with the unit and replacing everything that needed replacing. The problem is I have to do everything myself! down here a problem that you wont have. O.K now let me tell you what went wrong.
1. Within 25 hours spindle ceased up, and wouldnt work. They replaced all 3 free of charge and have had no problem since, with over 225 hours so far.
2.mixer problem caused loss of power. They replaced it free of charge, but that mixer is faulty and am now awaiting new mixer that I have not recieved yet. Enviro guard to blame!
3. My Left rear shock failed. They again replaced it free of charge. That just happened 2 months ago, and all others seem fine. Just bad luck.
I think Ferris is a very good company with excellent customer support. The lawn mowers suspension is awesome allows you to cut rough areas in half the time you could do it with other comprable mowers. The propane does burn way cleaner than gas which is seen when I do my oil changes. My hustlers oil is black and evidently thicker. The Ferris oil looks as if it has half the hours though both machines have the same hours. When we bought it in the states my wife filled one of the tanks and it came out to $45.00 U.S. Here I fill both for under $30.00. I hope this helps.