Finally one, I can answer from recent first hand experience.
within the last couple of weeks, I have flown AA PE to NRT from LAX and returned from NRT to YVR on JAL Economy. There is no contest. AA PE was hands down better (especially if you get the bulkhead). Loads of space and recline. JAL felt very cramped in comparison and the food was horrendous. AA PE had a very decent meal.
If you can swing the extra $$, do it!