Just flew FRA-YVR on Lufthansa in J upper deck. I had not had a chance to be in "the bubble" since years before when some airline (can't recall which) had a Y upper deck configuration, and I still remembered the feeling of peace and isolation compared to the rest of the plane - it made even Y feel like business. Upper deck in J is the best in my books, and yes, there is a slight delay in disembarking compared to lower J but honestly the quiet is well worth it.