Just to add my $0.02: BA wins for quality and consistency of food and service, and seat for sitting. VS wins for ground services (check in and lounges, although priority boarding just as bad as BA, if not worse), bed, sleeper suit and privacy in the air.

One macro point: if you are big (tall/broad or otherwise large) then VS is much better. I'm tall and broad (think rugby second-row) and the NGCW seat is just not long enough (unless you manage to score one of the small number of extra-legroom seats) to sleep comfortably. On VS (particularly on the top deck of a 747) the beds are a decent length which makes all the difference to me.

If the seat matters: BA
If the bed matters: VS
If onboard service and food matters: BA
If ground service and lounge matters: VS

etc. etc.

BC