Code reviews serve several purposes including quality and spreading knowledge.

Robert Glass suggests that "RI1. Rigorous reviews commonly remove up to 90 percent of errors from a software product before the first test case is run." ( http://www.computer.org/portal/web/buildyourcareer/fa035 )

He has several related points and extensive discussion in his book 'Facts and Fallacies of Software Engineering'.

One of his key points is that code reviews (he calls them inspections) are the closest thing we have to a silver bullet in a field that actually has very few of them.

Kudos to putting quality first!