The key to great SEO is to remember what Google’s ultimate objective is: creating the best search experience for users, so they can find the best, most relevant results. Rich snippets are a prime example of Google trying to do precisely this.
The goal of a product rich snippet is providing users with additional information about a specific product, such as the product’s price, availability (whether the product is in stock), and reviewers' ratings and commentary directly in the search results.
According to SEOMOZ you can get up to 30% click through rate increase with rich snippets in your e-commerce.
Richsnippets from QuirkyFoxLabs is a Magento extension that adds the Schema.org markup in your product pages. You just need to install the extension and, without any files modification, it will add the Schema.org markup on the fly in every product page.