now, US Air miles kind of suck. They aren't nearly as easy to use as United or AA miles. You can't book one way award tickets which is the biggest kick in the balls imo. But, they are really easy to get. Plus, you can use them on United or other star alliance airlines (not for United one ways and you have to find the flights you want and then call them with them as they suck at finding them for you). also, with rumors of AA merger, they may be turned into AA miles in a couple years. That's the direction they would go imo as United is the premier domestic Star Alliance carrier and AA is the only US domestic carrier on One World.