It's not just the CC
If you'll permit a still, small voice from the cheap seats.
For nearly twenty years I flew BA, mainly transatlantic to the West Coast of the US. On the vast majority of trips, whether economy or Club, I was looked after very well by attentive crew. Most CC were intelligent, charming, genuinely nice people who seemed to work quite diligently to look after us.
I stopped flying BA because of the BA marketing department.
In their wisdom, they decided to discard the few remaining founder subscription members of the BA Executive Club. Basically, having told us that we'd all remain free Silver members for life (and so entitled to lounge access) -- six months later they withdrew membership. For the first time ever, I wrote to an airline CEO (Eddington) to complain about their cavalier and callous treatment of their most loyal customers. Complete waste of time.
I -- and all my company's staff -- have flown Virgin ever since (because they let me use their Clubhouse) and their service is at least as good as BA.
So it's not just the CC that affect choice -- it's all sorts of factors. BA won't get me back now, regardless of how super their CC are.