I'm trying to achieve those levels so I am motivated to stay with carriers on which I can earn MM/lifetime status. AA is my primary carrier and offers good benefits for 1MM and 2MM, as well as nice gifts for each MM level achieved after that. I also earn miles on QF (Qantas) and they have decent benefits for their equivalent status levels.
UA is marginally appealing as a third carrier but it would take a very long time for me to get to 1MM with them as a third carrier. NW offers recognition for 1MM but no benefits. US and CO do not offer recognition at all. DL has made it almost impossible to achieve 1MM, 2MM, or 4MM for lifetime recognition, but on the plus side, their benefits at each level are pretty worthless so it's not tempting to buy any fares on DL anymore.
I don't see myself defecting to anyone else after hitting 2MM/AA and lifetime Gold/QF just because the status will always be there for me otherwise. If UA improves their benefits, I might look at more time w/them. Otherwise, no.
[This message has been edited by Spiff (edited 05-30-2003).]