Cut and paste from my post on a different related thread.

I have been about as close to an exclusive Delta customer since my first solo flight in 1972. I have flown on other airlines and earned status on them as well: United/USAirways/TWA/Piedmont/PanAm. Despite vists to the other side I have remained with Delta.
With the Skymiles ReDo it appears that there is no longer an incentive to be loyal to any airline. I will use my PM benefits until they expire and ride the status downgrade train until I hit the SM level where I will remain as a 1MM.

I am not defecting to anyone, nor seeking comps in other airlines programs. I will simply choose the best flights for my needs on any particular trip and from '04 forward, sit in the back.

TW