In my experience the only people who trash Colnago Supers are those who don't have one, and/or wish they did.
That said, like many of us,I did see a few Supers in the early 80s that I'm sure Ernesto wished he could have had back. They did him no favors. Mainly terrible paint and graphics.
As I and others have mentioned here more than once, the Colnagos to look for are the Supers from 1969-1974, and the first generation Mexico (a way-cool bike), from 1975.
After that, the bikes/frames are a little less interesting, although the basic Super remained mostly unchanged, except for mild graphics changes and lug decoration/finish, until about 1980.
I expect those early Supers will be in the elite category of collectible lightweight from here on in. I know they're getting harder and harder to find in good shape, and when they do come up for sale in a prime size, there's a lot of interest in them..
I think a clean, original frame/fork only in an early Super would nudge close to a grand, if marketed right (read, good pics and description on ebay) and a good size.. a clean, original bike with all the right panto'd bits and original wheels in good shape would come close to 2K, or more, right now, easy, *in a prime size.* Tall ones will usually go for much less, and have done so even recently.
I think most of those old Supers were bought by guys who *rode* them..really raced 'em for many seasons.. I've seen a number of them over the years that were really beat. So if you find one in your size and it's clean, I'd snap it up, 'cause they just aren't there for the picking anymore, if they ever were, to tell you the truth.
Charles Andrews
SoCal