A380 is 2-3-2 while 744 is 2-4-2, so if you are unlucky enough to be in the middle, its mildly better.

A380 PE cabin is upstairs at the back, while 744 is sandwiched between J and Y. A380 has some spacious seats, particularly row 38.

A380 is completely separate from rest of plane, with own toilets. 744 uses Y's toilets

A380 has self service bar, 744 does not

Some people say A380 PE is sometimes the last off the plane given it is at the back upstairs, meaning big queues at immigration.

A380 may get subbed for a 744 if there is a tech issue, which happened to me on Wednesday!! After I had shifted my trip to fit in with the plane's schedule!