You can credit all Oneworld flights to any of the 8 OW member programs. Each program has different features, making it quite hard to determine which is the best program. Often Aadvantage is optimal, but BAEC and CX Asiamiles all have some feature that is best in some conditions. So it depends what fare classes you are flying (they earn differently on each program) and how you want to spend the miles. Usually using more than one program is sub-optimal, until you get into the high end.