The Upper Gunnison and the Gunny Gorge are two vastly different runs.
The Upper Gunny is nothing but a meandering, class II gravel bar river. Its open, in the sun, and easy. No rapids, only an occasional irrigation structure to run. Fishing and naked floats are hot right now.
The Gunny Gorge is a class III run located in the bottom of a deep gorge. Hard to access, lots of (easier) rapids, and like Stiff said, the option of doing an overnight.
Which one is most appealing?
"Don't f$&@ing eddy out, just run it! Whaddya doin??" -LMyers