Another vote for CX. Their business class (other than SQ) is the best. Long flight from the US to Hong Kong. Great place for a few days. Then buy a ticket inside Asia to places like Bangkok (interesting city, lots to see and do, great food). If you like beach go to Hua Hin or fly to one of the islands. Other options are Bali, Saigon. Then get an award one way from your last destination back home.
Personally I am not a fan of BA. Their F is a glorified business class and their business class is too cramped. Also careful with JAL because they still have lots of planes with the old business class with uncomfortable seats. Personally I avoid AA. Their new seats are nice (similar to CX on the 777), but everything else is hot or miss (more miss than hit normally).
And yes, after you experienced a good airline like CX in F or C you will see that it is miles well spent for a 15 + hour flight.