The CO President's Clubs are leaps and bounds nicer than AA Admiral's Clubs. PCs have free internet, free booze, and you can use Delta's and Northwest's clubs. I live in Austin and AA and CO serve the destinations I travel to most about the same, but I stick with CO because of the PC and the UGs. If you live/travel to a city served primarily by one airline over another, your rationale would be different than mine.