A380-800 driver, you conveniently left out the comparison of the Basic Operating weight of each aircraft type as that would give a true indication of the potential payload. We all know that the Dugong is designed to be stretched and thus the Wing/Centre Wing Box structure is bigger, stronger and heavier than what the current -800 version requires - in comparison, the B747-8 wing/fuselage is designed/optimised for the current version, ie they will not be carrying around any excess weight (probably in excess of 100 tonnes) and thus will almost certainly have better fuel/payload/kilometre figures. Some people deride the B747-8 as being old technology but as it has an entirely new wing, partial fly-by-wire controls, GENX engines & associated systems etc, I believe that its operational performance will stack up very competitively with the Dugong.
Wrt your post #114, earlier in this thread, the question was posed as to which of the two new Boeings would start test flying first. My posts were simply showing that the race is still on.