My issue is noise (specifically audible vibration). I like 9A/L for the large shelf, footwell, and privacy, but increasingly find that anything near the engines has an extra dose of machinery noise when the seat goes flat. I don't mind the constant "rush of wind" noise as I can reduce that with earplugs plus Bose, but pulsating machinery noise is hard to tune out, and piles of pillows and blankets don't seem to dull it much in the lie-flat position. 1A has always been my favorite but is usually unavailable and I am no longer enamored with row 9, so it's middle of the forward cabin when I can get it.