I was UA for the past couple years and finally gave up this year having lived in MSP for the past 3 years. That said, I did enjoy this past year on NWA. The not having to connect in ORD every flight is nice. ORD really is a pit.
I would say the NW program overall is better than UA. UA has really devalued their FF product this year. Being elite insulates you from it but all the moves left me with an icky feeling. The 100% bonus at gold on NW is nicer than 50% on UA. And the unlimited upgrades has been way better than the e500 system. Plus my wife likes the companion upgrade which there was no chance of ever getting on UA.
Now I have to hold my breath to see how DL ruins the program.