This was one of the first types of structured data that really popularized structured data within the search / SEO community. This is also the easiest way to enable “rich snippets” sometimes referred to as “star ratings” in the SERPs. Google has not only documented this type extensively but it is one of the few types they’ve done a video on as well.
This example taken directly from Google’s documentation.
When executed properly, Google will give you a nice “rich snippet” in the search results.