As a frequent ULH A380 flyer in Y (DXB - JFK) for several years in the past, starting 2008, I prefer to sit in the first mini-cabin. Benefits include quick access to the loos up front (5), first to get off the plane and clear the immigration line, easier access to the galleys in case you need something mid flight, and a lot more area (galleys and behind row 50) to walk and stretch yourself mid-flight.

I almost always prefer aisle seats on ULH flights, and on the A380 it is the aisle seats of the middle 4 seater for me. My reason (apart from the fact that there is only 1 person who needs to cross over) is the way the 'foot spaces' are arranged on the A380 due to the placement of the seat supports. So the 2 aisles seats in the 4 seater on the A380 get their individual spaces and so do 2 the window seats. The rest (middle 2 on the 4 seater and aisle + middle on the 3 seater) have to either be nice and 'share' the space or play 'footsie'.