I always preferred US FA's to UA FA's, because UA were generally older, unpleasant, and could care less about you. (And this was pre-merger) Though I only flew the US carriers a few times a year when I was living in Hawaii, and it would be when it was too expensive to book AC to YVR or YYZ and then a second booking back to the states. (Because you can't book US-US even though AC is so much more pleasant than US carriers.) But now, living in the UK, I only flew US once last year on a domestic flight on a trip visiting my family. I definitely avoid USA carriers as much as possible.