What are your primary destinations?
What types of fares do you tend to buy?
<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by FlyBoy2:
NWA is very liberal with upgrades but not certain that it is the best choice for total USA/Canada travel.</font>
Actually, NW is really only a program to choose for domestic flying. International benefits are really quite limited.
One plus for NW is that if you're flying DL on the lowest fares you'll earn one elite mile for each mile flown rather than the .5 mile that DL will credit. In other words, flying DL on low fares it's better to credit the miles to NW than to DL!