Hi Kid -

As a Northwest Silver Elite I've actually had better luck upgrading on CO flights than NW flights. CO seems to be treating my NW elite status exactly as though I had the identical CO elite status.

I suspect that Pushpak's experience was that first class was simply full by the time he tried to upgrade. Part of the problem is that CO does not do an automatic upgrade for Platinum or Gold members (either CO or NW) the way NW does; in other words, you have to call in and request the upgrade (or do it at the airport). NW Platinum or Gold elite PAX who don't know this and therefore don't call in two days ahead of time sometimes can't get first class seats at the last minute.