I was Plat on AA, and switched to CO in 2001.

I will fly to the ends of the Earth to avoid coach on CO; I never felt that way about coach on AA. I honestly don't know if it's due to FC addiction on CO or the fact that AA really does have more comfortable coach seats, but if you don't score an exit-row seat on CO, and are at all larger than average (I'm 6'3"), you will feel cramped.