I’ve flown BA first (a long time ago), also Swiss and Emirates.
BA first crew were superb, as were Emirates, with Swiss being noticably less so, e.g. overstating everything including loudly explaining the dinner, course by course, at 0300, when some of use were tucked in and trying to sleep.
What BA service is like these days, I don’t know, but I think Martyn calls it right when he says “the new cabin was that it was not as memorable or as noticable because the crew were so absolutely fabulous, it was they who made the flight so memorable.”
My (6) EK sectors were all on A330, with an okay, but far from great F cabin, however the service was so good, it was irrelevant.