Hello! Recently used Qantas premium economy QF63/QF64. I considered the cabin class a reasonable substitute for business. I managed to get quality sleep both ways. Quiet cabin and good wine. 36J, 36K provide extra room but can be a bit noisy as next to galley. No problems with 38K and J. Only complaint, need a design degree to operate the seat and the foot rest is a bizarre waste of effort.