I'm not sure what class of service you're flying, but AA is a perfectly good choice on JFK-LHR. I'm assuming you're flying Y. If so, then as long as you're on the AA 777 (which you will be on this route), it's a good trip. The seat pitch is, IMO, generous. There is decent IFE and the food isn't all that bad. I'm not sure what more you'd except from an airline in Y. I've flown various airlines in Y TATL and have found AA to be amongst the best (as long as on the 777).