Hi OP

I regularly fly to SFO on the A380, and also frequently (unfortunately depending on cost) do the slog in Y.

I have a huge preference for the upper deck in the A380 if flying Y and always try to take window seat so that I can use the huge bins that are great for storing iPad, headphones, drinks, jackets etc.

Only downside is because of this space you can't lean your head comfortably against the side of the cabin for a nap, so you need to be able to sleep sat up.

The cabin feels a lot more intimate, and also because its smaller, not so busy and so feels more tranquil.