The grass is not always greener elsewhere though, although having put in trips on BA recently outside my previously limited AMS-LHR route, I can now make some comparisons.

Current reasons I see for me to prioriise a booking to BA are just

i)You are BAEC Gold and get 100% Avios bonus on base miles
ii)You need 2x BA metal for Bronze / 4x BA for Gold/Silver flights to go with TP/avios deposis from other Oneworld flights
iii)BA Gold 3x 32kg allowance great when I am lugging my SCUBA gear from A-Z locations. Just my boxed up CCR weighs 32kg, without any open circuit kit(regs/bcd etc). 60kg just scuba gear to checkin sometimes.
iv)Monopoly on slots and route-network out of LHR

Some of my reasons to avoid BA
i)old seat/ife hardproduct in cabins compared to some other airlines, now middle of the pack instead of leading the pack
ii)CR has fallen away, if a very poor flight virtually no makeup recogition (5-10k avios if lucky)
iii)BA not interlining, most other Oneworld partners have already back-tracked eg MH, CX etc
iv)BOB is a disaster area
v)Far East flights you get more TPs by stopping halfway flying with ME3 airlines, compared to direct BA flights. (such decision is nothing to do with BA's hard/soft product though)

Some of these negative reasons equally apply to other airlines eg
i)ME3 are great until you have bad flights, and then find ME3 CR teams are either indifferent/useless/non-empowered
ii)EC261 - BA may try to put you off to some extent but will pay out, but some other European airlines just refuse to payout with madeup excuses, unless you issue proceedings.