Im on AM almost monthly just about. As a silver (thats what I am) you can choose any main cabin seat, no charge. I've gambled a few times on a rt ticket in coach. I was upgraded at the gate at ord to mex but wasnt on the way home. In Aug I went to Chihuahua for a few days but didnt get upgraded, full plane. I think their ff program members might get priority and thats fine with me. I would rather get DL miles since I live in the US and DL has a more extensive route map than AM. Although I prefer AM fa over the tyrants on DL.