IMHO, the problem isn't necessarily with the quality of the agents, but your ability to get through to one in case of widespread irregular ops. I once spent 20 minutes in the hold queue waiting to speak to a DL reservations agent (general number) regarding a paid F ticket when I had to give up. (I took alternate transportation and no-showed for the flight).

I have no idea how good or bad AA's wait times are for general members, but I have had horrendous experiences with both DL and NW.