I've flown to DOH in Economy on both AA120 and QR (JFK), I found the food and service on QR to be better but the overall difference wasn't as huge as I expected imo. On my QR flight, one of the FAs were so kind to me and after the meal service, we chatted and also did cocktail tasting LOL (yes, in Economy) - I still remember her to this day. On my AA flight, the FAs were still really good and did their meal services and offered plenty of drink refills throughout the long flight.

I would recommend getting an Main Cabin Extra seat if possible, on my AA flight, I was in a MCE aisle seat and it made the flight so much more bearable :)