During 1999 I will earn enough miles on NW/CO to achieve silver elite status. Question: which elite program should I opt for? There is reciprocity between them, but not equality, so it seems. Please feel free to contribute pros and cons of each--for my decision. Pros seems to be favoring CO.

Pros for going silver elite with NW:
My wife will be silver elite on NW, thus both have same status/same program (I value simplicity). NW gives you 500 bonus miles per connection. Issue paperless upgrades when using fflyer miles to upgrade, no certificate that comes via mail, as with CO.

Pros for CO:
In-flight entertainment, NW has no movies on longer flights. CO will allow you to purchase up to 20 percent of the miles needed for a travel award. CO can waitlist you for fflyer upgrades, NW cannot--either the seats are avail or you don't get the upgrade. CO has more modern fleet than NW. More car rental partners.

Last thing: does anyone suspect that a married couple flying together, one with NW silver elite status, and the other with CO silver elite status will receive different treatment or priority on upgrade, eg. on CO? That's my only concern.

Of course, I could ask CO to comp my wife with silver elite and we could both be CO silver elite...

Thanks in advance.