I'd probably go for Amex because they can be transferred to Delta or Flying Blue or Virgin depending on which has the availability for your flight.
Keep in mind your Amex rebate is not the same as an award flight. 200k points is a $2000 ticket (before rebate).
Also I don't mean to change the subject but double check your research on AF having "the best business class". Those A380 planes for the nonstop service aren't lay flat.