I'm not a huge fan of either DL or AS F, but I think you may find AS F a bit more comfortable for longer flights... Most (if not all) 737NG aircraft have the foldy-ear-rests in F, and IME the cabin crews are as good or better on AS. As a DL flier, I don't think you'll be disappointed. My vote: bring a laptop/iPad/portable DVD player (and extra battery if need be--no at-seat power), and book the AS flight.