Originally Posted by
lamont2718
As an American male with above-average height and 30-inch waist, I find the 763/764 J seat very comfortable for sleeping on my back and on my side.
+1
From my experience, the 767 J seats are the best in Delta's fleet.
747 ones are odd angled and have a narrow foot compartment (you cannot stretch out both your legs at once, practically, while sleeping) and nowhere to put your knees when sleeping (yet you have to bend the legs, as it's very narrow in the foot compartment, the "mini coffin"). A330 ones are even worse for all the same reasons. And 777, surely the worst of the pack, with a very narrow at top headrest.
So, from my personal experience
767 > 747 > A330 > 777
for DL BE seating.