GD Star Rating is post, page and comment rating and review plugin for WordPress. Plugin supports different image sets, rating moderation, vote rules, time restricted voting, templates, trend calculations, multi ratings, templated rendering, has a widgets build in and extensive shortcode support. Plugin can be integrated with comments for making a review website.
Plugin support for comment integration for setting up the review based website. Also, you can reorder posts using rating results fro archive, front page or anything else.
For the most part, plugin is compatible with WordPressMU.