Ask me again in a couple of weeks - I'm doing BA to LHR tonight, then BA to/from Cairo next week (when I understand they should have introduced some new aspects to the soft product, though they are day flights so I won't see all of them), and CX back from Paris after Easter.

But what I expect (based on my experiences a few months ago, and based on the 747 BA vs CX new F):

Seat: CX much better than BA as a bed; as a seat I actually prefer the BA one because it has some lateral support.

Environment: CX is better because there is much more space (9 vs 14). But BA still has overhead bins, which I prefer to CX's solution of putting your bag underneath the ottoman (the wardrobe is only really big enough for a laptop bag).

IFE: CX by many, many miles: the screen is about 4 times bigger and the selection of content about 10 times.

Food: BA by a short head in my experience, excluding the caviar of course.

Wine: Close, but again I think BA had it last time round.

Service: they're both pretty good in most cases. CX has days/crews which are way better than BA has ever been, but they aren't so common these days, particularly with a full cabin and one less crew. With BA I suspect being British and having a quick banter with the crew on boarding helps.