While I agree that coach award availabilty is difficult on transcontinental journeys and to exotic destinations, when comparing to other programs it is no worse. And AirTran has much better availability to move around in the eastern United States.

And AirTran awards are one way: if you can find a segment open you can book it without wasting miles on a round trip.

Most importantly, AirTran has good availability for the free Business Class award. With their program, you pay "double miles" and get a first class ticket -- with legacy programs, you pay inlfated mileage -- sometimes more than double -- and often get convoluted coach itineraries.