Originally Posted by zurichflyer
I am member of both FlyingBlue and Skymiles, since there are differences:
- Skymiles can be used for upgrades on Delta, and the six PMU are nice for transatlantic upgrades
- FlyingBlue miles can be used for upgrades on AirFrance or KLM between Asia and Europe, and can also be used on first class awards on AirFrance, which is not possible with Skymiles.
if I were living in the US as the OP does, and were to travel enough to be PM, then I would definitively switch to Skymiles for the Medallion upgrades and the PMUs.
on the other hand if you live in the US and fly NW a lot, you get free upgrades with FB plus lounge access; also a pretty good deal.