As many posters have said it really depends on your tastes and needs and I would caution taking an individual opinion of any airline which will be based on their own wants and needs.

I would actually break this down into

Which alliance best serves my needs? Within that alliance, which FF programme would give my expected flying pattern that best rewards for me? And which airlines would I fly to individual destinations, which does not need to be on the FF programme selected.

Things like 💺, 🥘, these are often very much peoples personal tastes, I would encourage experiment to find what suits you.

if your London based, OW does provide a good amount of P2P flying. If you travel within the states, having a OW FF programme that is not AA means that you get premium drinks in AA lounge without having to pay for them.

Good luck and remember, no plan survivors first contact with the enemy