In my opinion, the R5 is the better combine. The R50 is basically a shrunk-down version of the R5. It has a smaller feeder house, rotor, and shoe assembly. The R50 has the air-cooled Deutz motor, it's a good motor, except when you have to work on it. The Deutz motor, being air-cooled, eliminates all problems associated with liquid cooling systems, but the cooling fan blades wear down and the fan assembly is very expensive to replace. The hydraulics are where the radiator would be, so it would take a lot of engineering to put in a different motor if the Deutz blows. At least with the Allis motor in the R5 if it blows it isn't that hard to put a different motor in its place. Good luck!
