zan5hin - it seems you don't expect sufficiently large amounts of travel that makes earning in 2 programs worthwhile. Thus to me it boils down to what you would value more. A higher status with QF, or more redemption possibilities with AA.

Personally in your situation I would probably go with AA. The difference in benefits between OW sapphire and OW emerald is not that large, and if not expecting to be travelling that much in future the extra benefits of OW emerald are not worth a lot. OTOH if I could get a lot of QFF points through credit card spend, that might tip the balance. But it would need to be at least 30,000 a year to offset the worse redemption rates (+ higher "taxes") with QFF.