Well, if you want free upgrades, try NW. You will sit up front a lot, maybe not every time, but a lot. Oh, just so you know... LAX has a reputation for being a tough upgrade, but you should know that certain flights you will have STIFF competition, even as a PLAT. Thursday night redeyes to the hubs, for one. NW has had a better ratio of "real" jets to CRJ's than most other airlines, but that may change with the downsizing. The hubs in MSP and DTW aren't terrible, and neither are "legendary" for delays like ATL is. Throwing on connections to your destinations as you would with NW will get you status faster or with less effort than flying nonstops as you are with DL most of the time. T2 at LAX ain't the best in the world, and the WC there now closes too early to be of any use on the redeye departures.

Amongst the SkyTeam partners, presuming scheduling/routes isn't an issue, I think NW is the best for the cheapo traveller like me. NW cheap fares earn 100% EQM, DL cheap fares earn 100% EQM for NW WP, NW has more F seats than DL (read: more upgrades), and I think the base milage bonus is higher for Plats as well (is DL at 125% for their plats on their metal?). However you will *not* get upgraded on DL with your WP status. I write CO off most of the time because of their 50% EQM policy. If they would allow me to book on CO.com and get 100% EQM, I would have a different attitude. The EQM thing is such a deal breaker that I haven't flown CO metal this calendar year and I will be plat after my next flight.