After using my father's Kubota for several hours I'll take the Ferris every time. A suspension is the way to go. If you're concerned about time, I would think the suspension would serve you well as you're not having to slow down so much over the bumpy stuff. The 3100 is built very well. I'll never wear mine out. My mower is used for my own residential purposes. I don't mow commercially. I've found when buying stuff like mowers you might as well buy something made for commercial use, it makes life so much easier. Yes, it's more expensive up front but the ease/time savings/comfort is well worth it.
I plan on lending the Ferris to my Dad to try out on his property. I think once he rides the Ferris he may want to switch. He's in love with the diesel and stated he absolutely wants a diesel. The Ferris diesel is quite pricey.