I am an AA Platinum and have no complaints. From what I hear of Premier Exec, there are way more PE's than AA Plats, hence reducing your chances for upgrades. I have also heard (please excuse the hearsay) that the customer service for PE's is terrible. They have too many 1K's and even more PE's. As for AA, I have received domestic upgrades most of the times I have requested, and the service from the Platinum phone line is excellent. I have heard that Exec Plat is even better.
As for routes, IAD is a huge hub for United. American has a very small presence in DC. (Some DCA, some IAD). Good luck with the choice.
[This message has been edited by gwade (edited 05-08-2001).]