My father just went from a 2wd 50hp MF Industrial 35 (50hp Perkins, monster loader, loaded tires, wheel weights and chains) to a 4wd Kubota L3650 (~36hp, four loaded tires, much smaller, tighter turning radius, cab).
The Kubota will pull the 10' offset disc that he has better than the Massey used to. Time will tell, but I think it will be more useful than the old tractor was due to the fact that it has a better power to weight ratio and 4wd.
Aaron Z