If lounge access is your biggest concern, Aegean in *A would seem to be your best bet. Redemption levels there are not great, however.

The most resistant to DL's big anti-consumer change is probably AA, as they have been working to snake elites upset with recent anti-customer moves at move UA and now DL. They would be in a bad place to turn on those elites they have pried away from UA and DL by repeating the very things that drove them away from those airlines. They seem to be posturing themselves as the firewall, if there is to be one.

NW was the airline that put it's foot down and said ''no'' when DL last tried to devastate ff programs in the Rob Borden era. The airline most likely to do so this time is AA. It was a sad day for air travel when DL took NW off the board.

Also, most of UA's partners earn only partial or no milage on many leisure fares, while most of AA's partners earn full milage (AB is an exception, but very significantly, not BA).