Two completely different tractors. The 584 is a utility tractor while the 1750 is a farm tractor. I don't know much about the 584 but did once own an Oliver 1755 (newer version of the 1750). The 1750 was a good tough approx 80 HP tractor. They were built in the mid to late '60s. Most were diesel but a few were gas. Earlier versions had a 6 speed trans with a 2 speed hydro power drive, later versions had a 3 speed powershift for a total of 18 speeds forward (2 x 3 for reverse). Good hydraulics, live PTO, cat II 3 pt hitch, dry brakes (easy to work on), power steering, 16.9 or 18.4 x 34 or 38 rear tires, heavy (solid cast iron frame). The 1750 could be a good loader tractor because of the solid hydraulics, but shifting from forward to reverse requires good technique.
It will depend on what you hope to do with a tractor that will help you decide which is best (utility or farm work).
OrangeGuy