I've flown AA F a few times on the B777 and it's not that bad at all. I still prefer the BA product but AA is not poor and certainly better than some other "first" products across the pond.

The flagship lounge at JFK is great for an American business class lounge but is nothing close to the BA Concorde Room ... or even the First or Club Lounges at T7.

If there is no alternative then stick with it but if BA becomes available (especially in NF) I'd go with that.