My current one is a 1995 R1100RT (1100cc boxer twin). I once owned a
1984 R80RT (800cc boxer twin).The newer one has: - fuel injection instead of carbs - more than twice the power - more than 50% better fuel consumption - brakes that actually work - ABS - low profile radial tyres with huge amounts of grip vs crossplies - a rigid chassis - unique front suspension design that soaks up the bumps but doesn't dive under braking - an alternator that can keep the battery charged even with mostly short trips .. I think it's something like 800W vs 50W.
That said, the old one handles *really* bad roads better, and is much easier to repair if you find yourself broken down in a 3rd world country.
-- Bruce