Originally Posted by UA 882
I still don't understand why you would want to switch. United is part of the Star Alliance which gives you a lot of choices for awards redemtion. The redemtion rates are lower than NWA, and are more easier available than on CO. They have a better route network to Asia and Europe compared to AA and CO, and the mileage promotions are always started by UA - if you are lucky, AA will follow.
Stay with UA.
One reason for switching is that I vacation a lot in Mexico and UA does not have a partner that flies where I go...AA & CO does. In addition, I will be flying to PDX and EUG, Alaska has direct flights to PDX from SNA and they are partnered with both AA & CO. I don't fly to Asia or Europe. In addition, I had a hard time using my miles on UA the last few years. I think the main attraction to CO is their UG policy and for AA it seems to be easier to redeem their miles. Unless you make IK with UA to don't get UG...at least with CO you have a chance...but I have been reading that it is getting tougher to UG on CO. I guess if I have to sit in coach...AA & UA would be better.