I’ve personally never found Google Product search all that useful, but hopefully that will change now. Google Operating System reports that Google Product Search has undergone a redesign of some sort.
In the past, Google Product Search just showed you results but did not group stores offering to sell the same product with reviews and technical specifications. Now, for some searches, Google groups store results, shows reviews on Google, and also shows product specifications.
For example, a search on iphone shows many results, but now there is a button to “Compare Prices.”
When you click on the result, you are taken to a page that shows the prices by the stores Google grouped together, with store reviews:
You can then click on more reviews to read more reviews from the seller’s sites or you can click on the technical specification to read product specs: