On the admittedly only handful of times I've called DL and AA in the past few years during regular ops, and I'm a nothing with them both, I don't recall a wait, or at least nothing longer than a couple of minutes. Of course, the one time I did have an issue with DL was when there were afternoon/evening thunderstorms in ATL, and then I had to call back for a day and a half - first to even get a line that actually connected, then to get a hold time that wasn't almost 2 hours.