First off when you read the Skytraxx passenger opinion section, you have to realize that the people who comment usually are the ones that had bad experiences. This is true about all of the airlines. More often than not you get people that have a very strong opinion with it either being good or bad. The horror stories that you read on there are fortunately pretty rare.
With that said, AA
in business class isn't that great. It isn't aweful, but not great. They are just starting to refit cabins with new lie flat seats. The current seats aren't that great. The service is about average. All in all, fly AA
if you want the miles or it is most logical for you, but BA
have fully flat business class seats and at least equal if not better service.
If you want a different experience, then you can fly Eos or Maxjet. If you want a premium business class for a decent price, then fly Eos. If you want to save money, fly Maxjet. Both serve Stansted, but they are a bit different.
If you have never designed an airplane part before, let the real designers do the work!