ive absolutely hammered the my 100, and its quite and rattle free. the engine never had an issue "cough.. head gasket... cough" the IFS is built sturdier and can sustain more wear with large rubber than the front axle of an 80, the live axle strength advantage is an old wives tale. the cabin materials are quite a bit nicer. the brakes are better, and the frame is much stouter and has more torsional rigidity. the dash doesnt show aging or button wear. if you compare 200000 mile well wheeled trucks, the 100 is way ahead. The 200 is another step, but its just too damn heavy and is past the point of diminishing returns, in my opinion.
A 461 G, or pre MBUSA is more ruggedly built than an 80 so an 80 doesnt get that title either. Its not a better wheeler than an 80, but it was designed 15 years earlier as military convoy rig and has inherent design limitations.
sure an 80 is great, but i'm not the "fanboy" type. I've been using a well modified 60 over my 100 or G, simply for weight advantage. It may not be as "sturdy" as the other two, or an 80 for that matter, but it shaves over 1000 pounds (500 less than an 80) on the same 35's traversing soft off camber, wet trails and its sturdy enough. the corners are easier to place and vision is just better.... and its more of a box.... i guess i am sort of a square fanboy.