Hard to argue with the zx20. They fixed all that was wrong with the zx225 and made it better. Individual switches instead of the control panel that was known to cause problems. 250 hp rating instead of 225. I would think the zx20 would be the way to go if I were making that decision.
FXi 21 is the way to go! Best rough water boat and speed to match. Sets higher in the water and on the trailer with the full 21 feet of boat. Big deck, stable and dry. Contact Monte at Fun N Sun and have them to take all 3 of the models out and run 'em. Good luck and have a successful fishing year!