which has a 4 BA flights minimum as well. BAEC has the advantage/disadvantage that the booking classes in premium classes have the same accrual rate, i.e. a discount "R" business class credits as much as an "J"/"D" business class. Moreover, you don't get tier bonus on QR.

The QRPC may be more interesting if more expensive fares (J,D, etc...) are booked, if OP can reach a high tier with QRPC in short time (tier bonus) and if QR continues to offer multiplier promos.

A combo of x5 promo and a tier bonus (the tier bonus is taking into account by the xN promos) could result in much more miles, than you could collect with BAEC on QR.