I've always liked the overall Alaska product, and as a SFO-based flyer feel that the combination of AS+VX will most likely convince me to shift the part of my travel budget that currently goes to UA (I'm usually Gold or Plat)---even though much of my UA travel is global and AS does not really offer partner lounge access and anecdotally I've had much difficulty getting partner points/EQMs to post.
At the same time, WN offers a very compelling product: gate to gate fast wifi free for elites, easy to change flights, big planes everywhere and the Mrs. travels free.