steve.barnett

Flexible hReview lets you add an <a href="http://microformats.org/wiki/hreview" rel="nofollow ugc">hReview</a> to a Post, then show that review anywhere on your site using the function or the shortcode. 
Also available on GitHub: <a href="https://github.com/SteveBarnett/Flexible-hReview" rel="nofollow ugc">https://github.com/SteveBarnett/Flexible-hReview</a>.
The options page lets you set:
<ul>
<li>field names for multi-dimensional reviews</li>
<li>the maximum rating</li>
<li>whether or not to calculate and display an average of the ratings</li>
<li>characters for before and after the rating text</li>
</ul>

Flexible hReview

Easily add hReview data to a Post. Show it anywhere using the function or the shortcode.

Aaron Queen

There are many sites that are crawling for user-generated reviews now, including Google Places and Google Local Search. WP Customer Reviews allows you to setup a specific page on your blog to receive customer testimonials for your business/service OR to write reviews about a product.
<ul>
<li>WP Multisite and Multiuser (WPMU / WPMS / WordPress MU) compatible.</li>
<li>All submissions are moderated, which means that YOU choose which reviews get shown.</li>
<li>Reviews are displayed to visitors in a friendly format, but search engines see the Schema.org microformat.</li>
<li>Multiple anti-spam measures to prevent automated spambots from submitting reviews.</li>
<li>Completely customizable, including which fields to ask for, require, and show.</li>
<li>Shortcodes available for inserting reviews and review form on any page or widget.</li>
<li>Works with caching plugins and custom themes.</li>
<li>Includes an external stylesheet so you can modify it to better fit your theme.</li>
<li>Reviews can be edited by admin for content and date.</li>
<li>Admin responses can be made and shown under each review.</li>
<li>Support for adding your own custom fields.</li>
<li>The plugin can be used on more than one page, and can be used on posts.</li>
<li>Supports both <code>Business</code> and <code>Product</code> review types.</li>
<li>Shows aggregate reviews microformat.</li>
<li>Fast and lightweight, even including the star rating image. This plugin will not slow down your blog.</li>
<li>Validates as valid XHTML 1.1 (W3C) and valid Microformats (Rich Snippets Testing Tool).</li>
<li>And much more…</li>
</ul>
Almost every new feature that has been added was due to the generous support and suggestions of our users. If you have a suggestion or question, do not hesitate to ask in our forum.
More information at: <a href="https://wordpress.org/plugins/wp-customer-reviews/" rel="ugc">WP Customer Reviews</a>

WP Customer Reviews

Allows your visitors to leave business / product reviews. Testimonials are in Microdata / Microformat and may display star ratings in search results.

Flexible hReview vs WP Customer Reviews