If you want to commit to a major airline out of MCI, I would probably recommend AA. I have Lifetime Gold on them, but I find myself flying YX and WN more and more often because they have cheap fares and plenty of nonstops.

My reasons:

- Most importantly: AA provides passable customer service to its Gold members. Not great, but not bad. United provided me consistently offensively bad customer service for my two years as a Prem Ex. I don't even know what it's like as a Premier.

- AA runs entirely MRTC aircraft to MCI. Mostly MD-80's, with the occasional Next Gen 737. (Obviously, there is no guarantee that MRTC will be around forever. ) United mixes in the RJ's from time to time. No guarantees that AA won't, but I have never seen one yet.

- AA earns full miles and allows upgrades off of any fare. Pretty simple U/G system, actually. As a Gold, I get enough upgrades to keep me happy. When I really want them, I have usually gotten the upgrade. (Admittedly, upgrading isn't a terribly high priority for me as long as I am on MRTC.)

- Having two hubs to choose from - ORD and DFW - is convenient for MCI travelers. Since we are right in the middle, we can usually find a reasonably sane connection to any destination in the US.

Comparing your routes specifically:
- LAS: Slight advantage to UA because of the better connect through DEN. WN provides nonstop.
- PHX: Slight advantage to UA because they have a bazillion flights to PHX via DEN, cumbersome connection on AA through DFW. WN provides nonstop
- LGA: Significant advantage to AA. Nonstop flight vs. ORD connection on UA. I think YX also goes nonstop, and I'm not sure if WN gets you into the NYC general area nonstop or not.
- South Florida: Slight advantage to AA thanks to DFW being a smoother connect than ORD. WN gets you into south FL nonstop (I think).
- LAX: Slight advantage AA since that's an AA mini-hub. Lots of DFW flights. DEN isn't a bad connection. WN and YX both go nonstop - WN into LAX and YX into SNA.
- YVR: Push. I am in the process of trying to find cheap tix MCI-YVR and nobody does this route well. Cumbersome connection everywhere, unless you want to do WN to SEA and drive.

In the past year or two, I've come to place such a high premium on the convenience of a nonstop that I've stopped avidly playing the FF game for my actual flights. (I'm still a freak when it comes to partner miles!) I'm flying to LAX, SEA, and DCA in the coming months, and I'm using WN and YX to do it - even though I might not be maxxing out my mileage potential. Connecting sucks.

Welcome to Kansas City, by the way.