It depends on what you want to do/how you want to use the points/miles that you will earn.
If for upgrades, then maybe BA Avios would be a better option.
However, if you want to use them for award travel (esp. premium cabin) then there is no better program than AAdvantage.
See my post # 160 (and several post after) about this here:
http://www.flyertalk.com/forum/briti...ntsguy-11.html
This is regardless of where the origin of your trip is (even from UK/EU, not just US).
Ps I do not know much about QF FF program but I believe the redemption are even more than with Avios.