My Tuppence worth as a fairly thrifty traveller.

Haven't flown the 787 (yet!) but having recently done BGI out WT and back overnight WT+ - I'd save my cash on the way out and hope for a flat bad for the way home instead. I'm only little but I can't sleep sitting up.

That said, having gotten onto the TP bandwagon and with the pitiful offering in WT these days, then that is a consideration.