Although the flexes are different(Fish:S-rocker, Cheetah:Traditional Camber) and the cheetah has less taper, they are both great deep powder boards, both really fast, both directional (obviously), I know the cheetah is heavy but I don't know about the 2013 fish, probably is. The flex is going to be about the same, the cheetah will be a little more stiff. There both gonna suck at the park. Lastly the cheetahs turn initiation is gonna be easier.
Have you ridden the fish and/or the Cheetah? If you say yes, I will be very surprised.