I use both the AA and BA lounges monthly at DFW. I would choose the BA lounge as the AA equivalent can get very busy especially as its AA’s primary hub airport. The BA lounge is a ‘one fits all’ lounge having recently done away with the separate First section. Normal fair in the way of food (sandwiches/soup/salad) and occasionally staff come around offering small sweet selections and tapas type tasters. I would arrive early as even though there is only one BA flight per day there seems to be a lot of transiting gold members using AA’s regional connections to Mexico.