All airlines have their ups and downs. About 12 years ago, BA service transatlantic was frankly crap, even in Club class, while American was very good, both in Business and economy. These days, I find it the other way round and rarely use American. Some of this may well be the fact that the American cabin crews haven't been that well treated by the company. One point I do find interesting about American, especially on domestic flights, is the lip service paid by CC to the safety briefing - probably because nobody flying in the US appears to take any notice.
About 12 years ago, I was flying back from the US. My wife had gone to her parents house as her mother had just died, and she couldn't remember which AA flight I was on, or where I was coming from, but needed to get a message to me. She called American in London at 2230 on a Sunday night, expecting that they'd get a message to me when I landed. It took 55 minutes for them to track me down to the Admiral's Club in Raleigh-Durham, and give me a message to 'phone her urgently. I figured that was superb service, although I have a feeling it wouldn't happen to day. I did write and thank the management, but they never replied........
Although give American their due, my BA Gold card gets me into their Flagship lounges when travelling on them in the US, even when it's not supposed to!