Also the QF crews on SFO-SYD are less tired than the LAX-SYD crews -- who have had a hard day and night of partying and shopping at LAX. So F service is markedly better out of SFO.

As for earning on BA TATL flights, these cannot be credited to AAdvantage but can be credited to BAEC or QFF. I use the QFF plan (finding it better for me than BAEC or any other OW plan). You can join QFF for free with a US address (there is/was a fee to join for Australians). The other advantage to QFF is that if you earn QF Gold (which is easy to do on an AONE4) you get free AC access for your US travel (plus free drinks at the AC). If you don't need the AA miles/status then it might be better to credit your whole trip to QFF (not generally true, as AA miles are typically worth double compared to QFF miles).