I have been op-upgraded a few times from Y to J in 2004, all the time they put me at upper deck. Last week returning to SFO from HKG, they upgraded me and put me at the lower deck, I ask them to see if they have upper deck offer, they said it's full. Then when I got to the lounge, I asked the same question, the staff give me a seat change to the upper deck. that was like 1.5 hours prior departure.

I like the upper deck, mainly because it's more quieter than the lower deck, and i like the extra storage space on the side, which I can store my shoes, laptops, amenities and etc..