I previously owned a commercial Hustler 340 with the 4 cyl Kubota diesel engine. It was getting up there in age, so I decided to buy a new machine. I chose the Hustler Fastrac HD with the 60" deck. The first time I mowed with it I noticed it rode ROUGH. I checked the tire pressure (supposed to be 8-12 psi) and they were way overinflated. I set all tires at 10 psi. Through the spring when ground is relatively soft, it rode great. Now that the summer heat has hardened the ground, it again rides like a Mack truck being pulled through a boulder field on it's roof.
One thing I've noticed is the seat is directly mounted on the hinged access cover to the battery and hydraulic motors. The only suspension is two small springs under the cover. I know they make a seat suspension kit, but, I figure when one buys a $7,000 mower, it should already be included.
Also, the drive tires/wheels could be larger. I have a neighbor who owns a Hustler Z and his drive tires are much larger than mine. Larger tires, equals softer ride.
Anyone looked at the aftermarket seats available for these things? I'm about ready to trade in my new mower for something that doesn't compress my spine every time I mow. It's so bad that my eye glasses pop out of the pocket on my tee shirt.