Depends what you value the most.

If it's getting to the top quickly and staying at the top for the duration of your use on OW, then definitely QF. However, their burn rate is not that great.

If you are looking into long-term mileage build up, then AA might suit you better as they have lifetime elite membership at 1 million (lifetime AA Gold=lifetime OW Ruby) and 2 million miles (lifetime AA Platinum=lifetime OW Sapphire). Plus AA counts all miles including bonus miles, credit card purchases, rental cars, hotels to that million miler counter so if you do a lot of travel in C or F, you rack up miles really quickly to become elite status for life ^