Google Search is always working to show the most useful and helpful information possible,
through testing, experimenting, and review processes. From this, we know people appreciate
product reviews that share in-depth research, rather than thin content that simply summarizes
a bunch of products. That’s why we’re sharing an improvement to our ranking systems,
which we call the product reviews update, that’s designed to better reward such content.
Source: Google Webmaster Central Blog
Link: What creators should know about Google’s product reviews update
