... but A vs B threads are so much fun.
I agree with the above statement that the 747-8F burns roughly the same as the -400F in cruise (and yes, with about 16% more volume, 20% more payload, and about 50T more total weight). However, I have noticed significant reductions in fuel burn during the T/O and climb phases of flight. This makes sense as a bigger fan should be more efficient at lower altitudes.
I think the relevant data comes from Boeing and Lufthansa. The per seat / tonne economics on the -8 are roughly the same as the 777-300ER / 777F. As per Lufthansa (and their respective seating configurations), the A380 has about a 3% per seat cost advantage over the -8I. One could further deduce that the same advantage applies vs the 777-300ER. I would be curious to hear from someone at Singapore as to their observed difference. Also, I am curious how much belly volume / payload is dedicated to cargo on a full, Euro-bound A380.