I left UA for AA a year ago for several reasons:

- AA had more reasonable mileage redemption polices (no need to buy the more expensive fare to be able to upgrade).
- AA treats their elites (even PLT like me) better than UA.
- Service on UA had gotten more inconsistent.
- Their ACs are more pleasant to hang out than UA's RCC.

To be fair, UA has several things going for them such as:
- Better route network, especially in Asia.
- Much more comfortable F/J seats.
- 744s!
- Their on-ground Int'l First service were outstanding, especially in NRT. (At least before they apparently downgraded the on-ground service, have they?)