Out of those I'd go with AA. My parents went Delta last year, on the way home their flight to Atlanta was delayed due to poor weather in Atlanta and they missed the transatlantic flight
. Delta did nothing for them in Atlanta, they were left high and dry to orgainse themselves for the night till their flight the next afternoon
. My in-laws however went AA through Chicago. On their way home they too were late getting to Chicago, again due to bad weather and missed their transatlantic flight
. AA had everything there for them on arrival in Chicago, hotel reservations, food credits transfers
.
So no contest in my eye's even if AA were a bit dearer.