The old AA lounge at DCA is a nice little set up. AAngels are friendly, and the view is nice. And having eaten in there I can recommend the turkey and Swiss toastie!. Can get a little crowded, but never not been able to find a seat. DCA is a neat little airport too, so might make a connection easier.
BOS is a bit dark, but pretty good.
Not been to CLT or PHX (Will go through PHX next month, so can comment then).