At least you got an upgrade. Been on a number of CO flights as a NW Plat to not get one...and although I can't prove it on paper, I know it was because good CO was upgrading their Golds and Silvers before me.
I think that CO's service is far superior to NW in many respects. But I think there is still a suspicion of NW Elites with a distinct preference for CO Elites.