The only downer with BA A380 business class is the old club world in the 2-3-2, forward/backward alternating seating arrangement. You said you're in 53K/L, but there is no L. Do you mean 53J/K? The only downside to those seats is that they are right in front of the galley where you might get more noise. Use the seat map in the link to see if there's something else you can move to that will be away from noise.

After flying AA F on a 777-300 with spacious 1-2-1 seating from DFW to LHR, you'll probably feel a bit of a let down on the return leg though it will be nice to have the long haul straight to LAS. Riding upstairs on the A380 is a cool experience to enjoy while they last. I've only done LH J on the upper deck and it was back when they were angled lie flat so I feel like I need to get on another one.