i only know about aa/ba/cx,

and i am ermald with all except aa, and now switching to aa as my primary one, though i will continue to fly ba transtaltantic.
my strategy now is put all BA transatlantic and intra-Europe in BA, and all non-BA miles into AA. i believe i can make AA EXPLT and still keep BA Silver (i already re-qualified for BA GOLD -- so no worry for another 24 months, but i continue to fly BA for transatlantic as you can see why, even though i found the BA miles extremely useless for me since i live in Boston -- i cannot issue CX award ticket, so i am wasting 80k miles to fly Biz to Europe, same amount you needed to fly from West Coast).

it seems aa is the best program. unless, LA/AY/etc can beat it.

BA: you can solve the atlantic problem by avoiding AA totally, but you wont have double mile flying cx, and BAEC in NA service is quite terrible IMHO. also, unless u r live in CX/BA port, it is very hard to issue award tickets from there.

the best compromise is perhaps to keep AA PLT plus BA Silver, if you have enough mile/segments

CX: the most stingy mileage award in OW, though they really serve you well.