If the dates work for you (JL's flight only operates 4x weekly), I would definitely chose JL over AA, especially since it will be a 787 with the SS8 product. As of now, discount J (i.e., I class) only earns 55% EQM if booked through JL with JL flight numbers. You could probably book the flights as an AA codeshare, with AA flight numbers, in which case you would earn EQMs as if they were AA flights. I am not sure if it would be drastically more expensive to book as a codeshare.