During my lifetime with LUS I was personally responsible for two full airplanes taking off late because they held them for me. It was a major inconvenience to the hundred or so other people on the plane but wow do you feel special when you land thinking you missed your connection and a US employee greets you saying "you didn't miss your connection Mr. Elliott, we held the plane for you." Twice. I don't feel that American would ever do this for me. I'm sure AA would re-accommodate me well, but that's quite a different feeling than we held this full A320 just for you.
I hate AA's multi-city tool. I much preferred US' where you chose each segment individually instead of how AA lumps it all together.
However, AA's food is better. Do any other LUS flyers remember domestic first meals? Your choice was "chicken with sauce" or "pasta with sauce" and both were pretty bad. I recently had the beef with lobster mac and cheese on a domestic flight and was quite happy.