Well upside is nice... but a lot of players in the past have had more upside than other guys and never lived up to it. When drafting I usually just tend to prefer whoever is most ready to play in the pro's asap. Football is a what have u done for me lately type game, and while it's nice to get Romo's and Brady's.. Guys that were afterthoughts, the general concept seems to be whoever can play better ball is the guy I want. I want the better player, not the guy with the most potential, i mean Clarett had tons of potential, as did Leaf and Couch, and A.Smith etc.
But with that said, the argument could be made either way.
I personally would take Quinn, he kinda reminds me of a Brett Favre ( scramble if i must, take risk if i have to, etc type guy as he showed when they played USC with a long run, and some gutsy throws against mich state) over a Russell who is obviously easily comparable to Culpepper( large size, big arm, quick for his size).
But hey, i'm not an nfl scout so it doesnt matter really what I think. Just wanted to add my two cents