I don't know what to tell you....
I have a 2006 SuperZ 60" XR-7 deck 28hp EFI Kohler, with rigid forks and air tires. Suspension seat with the flex seat under it. Close to 2K hrs on it. Second best riding mower I've ever used (next to my '97 DC Flatlander with ATV tires (4psi IIRC).
Did 2 separate MULTI-day demo's of the new SuperZ (Like yours 60" VX4 and 31hp Kawi) almost a year apart. First was with rigid forks and second was with flex forks.
The ride was fine. I did have a little more back-slap, but I attributed that to me being used to my easy chair like flex seat. When the Flex forks were added, it REALLY made it ride nice.
Maybe it was the increased power, the far superior cut quality, or the super refined feel of this new hydro system that was dulling my senses with regard to the ride? In any event, it rode just fine for me.
Don't know what else to tell you.
2004 GMC 2500HD Reg Cab BOSS 9.2 V-Plow
2013 eXmark LazerZ X-Series 60" 34hp EFI (RED) Kohler
2006 Hustler SuperZ 28EFI 60" Power Chute Design OCDC SOLD!
1996 48" SCAG Belt WB 14hp Kawasaki Classic Deck
Echo 2 strokes PB-755 & SRM 280
Eastman WM20H 20" Commercial Push mower (NEW for 2013)
Commercial Lawnboy trim mower 3-FOR SALE!http://www.lawnsite.com/showthread.php?t=424203
Solo since 1980