[mathattack]

Yes - building on this, I see 4 quick benefits:

1 - Suggestions on where problems have been solved before. (Your point)

2 - Having people say, "Here's the style we use to make this easier to support in the future"

3 - Mentoring on tougher problems, and turning quick hacks into elegant solutions.

4 - QA. (This is the stated benefit, but falls below the other 3)

The key is not to turn code reviews into a bottleneck. If you just view the purpose as any 1 of the 4, you're likely to under-prioritize or over-formalize it.