Hard product-wise, I'd have to go with AA F, especially if you're claustrophobic. Much more spacious feel both sitting up and lying down. I'd choose the new JL SS7 J if I wanted to be anti-social, and would make sure to have a window-seat for the best privacy + not feeling like being in a cubicle. And yes, this is taking into account the relative ages of the cabins.

For food and service aspects, JL wins. Food is better (not saying AA's F/J food is terrible, but JL's is definitely a notch above). Also plenty of things to eat throughout the flight on JL, but no sundaes. FAs are more reliably attentive on JL, and can be hit-or-miss on AA, even though the vast majority of my flights on AA have been with great crews.

So really, it comes down to what you prefer when you travel.