I'm on the fence on staying with AA or switching to UA - I'll decide on 3/1/2015 when my PLT status expires. I don't know where AA is headed but so far it seems as if Parker is trying to beat Smisek in the race to the bottom. UA/CO had their merger struggles and for the most part are now past them, while US/AA will soon be going thru their merger challenges. I don't expect US/AA integration process to be any smoother than UA/CO.
UA pros:
* Star Alliance network gives access to many regions in the world
* Website and app have many nice features (ie where is this plane coming from, inflight amenities, can make changes and upgrades online)
* Smisek gives ample notice about changes
* No extra surcharges on award tickets
AA pros:
* 100% mainline out of AUS
* First and business class are amazing
* 500-mile upgrade stickers which means better upgrade odds as not all Gold/Plat request upgrades on flights
* Power plugs on most planes