"As a basic member of BA and AA, which would you recommend for a new starter? Or would you recommend another programme?"

I would suggest the Qantas scheme if you are going to do a mixture of cheap non-tier BA point earning flights and flexible tickets. Domestic Flights booked in J on BA earn 30 status credits on QF and flights on the cheapie tickets earn 10 compared to 20 and 0 for those collecting to the BA scheme

You will reach OW emerald quicker with QF than with BA or AA.

Dave