Recently I worked on a review extension for the Omaha Wiki. They wanted to give users of the wiki the ability to write reviews for pages, recipe while still keeping control of the content and separating the factual information from the opinions.
The end result is VCReviews which combines the rating and review process into one submission, and is only accessible by logged in users. You can check it out at the Omaha Wiki. Just pick an article and click on a “reviews” tab.
Source is available: VCReviews Version 0.2.2