Remember when Google took over Zagat and then announced they are dropping the star reviews for businesses? Well, Google announced on Google Business Help that the five star system is coming back to the new Google Maps interface.
Jade Wang, a Google Maps representative, said "today, with the launch of the new Google Maps, we announced a change to the way people rate businesses on Google on the Google and Your Business blog."
Google uses a 30 point scale for rating businesses but now instead of using the text representation of it, they will be using stars. Here is how it is converted.
Forum discussion at Google Business Help.