Originally Posted by
piemel
If you are tall you want to avoid UD on the 747. Lower deck is much preferred in that case... but only if you're tall
The difference in seat length is only a few inches and, even though I am 6'6", that difference has never bothered me. Especially given the big benefits of the UD (less crowded, 2-2 seating, seatside storage on window seats, private cabin feel).
Caveat: I do sleep on my side, usually with knees bent, though (even at home), so if you are a tall back-sleeper, I can see where this might be an issue for you. Otherwise, my rule is:
747 C (UD) >>> 747 C (LD) > 777 C
On the 747 LD, I actually prefer rows 9/10 because of the isolation (middle 4 seats absent, taken up by galley and storage), but some don't like the brightness.