As a NW refugee who comped over to CO to escape the clutches of DL (which I know more than I want to from my years as a DL gold medallion), I would certainly not move in that direction. I want to earn miles that are worth something. DL's SkyPiles are the Zimbabwe Dollars of the sky.

I am taking a wait and see position and keeping my fingers crossed for the UA/CO merger. The thing that was a deal killer for me, as an expat who lives in a non-gateway city, for UA has been UA's deplorable practice of *Net blocking. If that is part of the merger, then I am gone.

That leaves AA and US, and AA is definitely the more attractive of the two. There are several downsides, one big one being too many connections on this side of the pond going through LHR (uggh!).

Hopefully the merger of UA/CO will work out okay with no *Net blocking or other deal killers. I really would prefer to stay where I am.

The Q400 is another big negative, though. From some itinerary comparisions on recent flights, it seems easier to stay on mainline planes on AA than on UA or CO. If UA/CO leaves me nothing but Q400's on the main routes I travel within the US, that could be as big a deal killer as *Net blocking