Very nice piece here, via Cal Bears (California Golden Blog) SBN site, where the author took the effort to discuss the problems with the NCAA quarterback efficiency rankings and statistically do new comparison with a different approach, which takes into account positive yardage gained by a QB and subtract the number of turnovers generated by the teams QB. Both Nick Foles and Matt Scott are closely bunched together in the traditional NCAA QB efficiency rankings (While Scott didn't play enough games, if you assumed he had AND stayed consistent, his ranking would slot him in third place). If you page down this article where he discusses the Pac 10, you see a nice table - with Foles and Scott as 4/5 out of 14 folks (not sure why Mustain isn't there, since he did cover some backups, which is how you get 14 players).
The traditional season long ratings (via the fine interns at ESPN) are here.
As you can see, Foles gained more yards than Matt Barkley. His completion percentage was also second only to Andrew Luck's -- where he is hurt is that, by comparison, Luck gained far more yardage, with a really high completion, all the while throwing 50 + less attempts than Foles. OTOH, Foles was also sacked more than six other quarterbacks.
Someone with more time and energy (and who passed statistics) would need to look at how many of Foles attempts were dropped, batted away, etc., to get a better picture at where Arizona needs to be next fall. A pie chart would be nice, I'm sure....