My experiences after a year with the Z997 and 72 deck.
Advantages: It will cut even tall grass fast both up and down hill and is relatively economical in fuel consumption. The suspension arm chair is comfortable on smoother lawn although on a rough field even that won't help the ride compared to a CUT with larger diameter wheels.
Disadvantages: You sit low enough that there will be times when you will get blowback from the deck exhaust on you and if you live in a known deer tick area you may pick up a tick or two. Also they are heavy and powerful enough that they will tear up lawn on non-three point turns unless done very carefully. This is especially true when turning on sloped areas. Also be very careful on downhills and side slopes with wet grass as these will easily turn into one ton sleds with minimal control once the rear wheels lock. The old style tall ROPS with the reverse cant would snag (instead of deflecting) trees and could easily give the driver an uplifting surprise if not careful. The 72 deck can be a little wide and cause scalping problems.