Hmm, tough call. For the AA comparison I am talking about 'normal' domestic F, not transcon or AFS. For BA I am talking mainline - not our friends at GB.
AA wins hands down on seating (obviously) - while their MD-80's are in no way luxurious they still offer far, far better seating than CE.
BA wins on food - just about. BA's breakfast is better, but I really don't care for the CE salad and find some of the other offerings indifferent. AA's food is pretty rubbish on the whole and I still don't get the whole sundaes fun. BA's booze offering is MILES ahead - the crud that passes for red wine on American makes the Dourthe No1 taste like nectar.
BA also win on general service - both consistency and quality. While there are some great crews on AA, there is also a lot of mediocrity and more hostility than you would want.
Of course, if you look at pricing it makes interesting. Domestic F is - generally - priced a long way above fullY, whereas the gap between J and Y on BA is much smaller (rarely over GBP100 r/t.)
If the choice of flights was a dinner flight on a FRA-LHR distance, I am very happy with BA. A LHR-DME/IST/LCA would be more pleasant on the AA product - CE seating isn't that much fun on those length sectors. CX's regional business class would be much nicer on either option.
But in the end, all comparisons are odious.
