Originally Posted by
Cathay Boy
Welcome, the ONLY benefit CX/AM has over against AA is level of services if you plan to move up the rank (for example at least GO level, DM level is no brainer you go with CX). When you say "extensively" you really need to do some math, again, if you plan to travel more than 40 sectors or 60K miles per year, then go with CX. If not, go with AA.
Why AA? Their awesome earn/burn ratio and bonus miles given. If you do 50K and make AA Plat you get much bonus miles, and then keep in mind it takes only 160K of AA miles to redeem round trip CX F class, or 120K for CX J class.
CX GO also gives you one extra check-in luggage if you tend to bring a lot of gifts and buy stuff aboard (6 luggage per trip, you can be your own moving company)
Anyway, there are tons of minor differences but this is the major one that should dominate your decision making.
If OP is living in HKG, a significant consideration should be the availability of non-flying earning opportunities, and even a light flyer -- maybe
especially a light flyer -- is better off with AM. Have a look at the credit card earning thread and you'll see that the earning rate per dollar spent is a lot more attractive than many other FF programs offer in their home markets.