You may also want to consider joining CX Asia Miles. you would get 100% on CX and LA flights and 50% for the BA and QF flights (better than the 25% with BA exec club) but this is only a mileage accrual program. If you want lounge access, you'll need to join the Marco Polo Club to earn status, which requires a US$50 registration fee.

Hope this gives you more options.