And the post Bucksnet referred to (which I can’t resist posting a link to) is at http://www.businesstraveller.com/discussion/topic/Calm-Under-Pressure-This-is-Why-I-Fly-BA?page=3
BA744fan – your original post has gone – perhaps when you tried to delete the thread. I don’t think any of us can know which deck is best until the plane has actually been tried out, but for what it’s worth here is my entirely speculative response. This is thoroughly biased by my own preferences and the fact that most of my long-haul travel is on my own, rather than with the memsahib.
I am guessing that because of its slightly lesser width the upper cabin – because of the lower number of seats across – will be slightly quieter. In addition, if you are in the middle block of three in an aisle seat, there is only a 50/50 chance your neighbour in the middle would have to climb over you (as against the other aisle passenger in the middle block). I am also assuming that the last row of rear-facing seats will have direct aisle access (as do the corresponding seats on the existing planes) with no possibility of anyone climbing over you.
So I would opt for 4AK or 8AK on the upper deck, failing which a D or G seat on the upper deck. I would avoid the upper deck middle (E) seats which – because the seat space narrows on both sides towards the feet as a result of the yin-yang configuration – must surely be a candidate for the most claustrophobic seat in the sky.