Along with a total revamp of Maps, Google has announced at I/O, the forum and their blog the return to a 5 star review system. You can request an invite to the new Maps here. From their blog post:

Users who opt-in to the new Google Maps will now rate businesses on a scale that ranges from one to five stars. The system maintains the precision of the former 30 point scale while improving the readability and accessibility of the business listings. Your customers will be able to find up-to-date, accurate information on your business faster than ever. As a business owner, you’ll notice that past ratings have been mapped to the five star system.

Here is how the new scores are now calculated:

poor/fair = 2 stars
good = 3 stars
very good = 4 stars
excellent = 5 stars

Some other notes from Google:

• Users on legacy Maps, mobile (Android + iOS), Google+, Google.com, and other properties will continue to see 30 point ratings for several more weeks
  • If a user is opted into the New Google Maps and clicks on a “more reviews” they will be taken to a plus page where they will see the 5 star ratings
  • However, if the same user had just navigated to the page from plus.google.com they would see 30 point scale
  • Note that users just searching on google.com not coming from New Google Maps will continue to see the old results.
• Google will no longer be asking users to rate on specific dimensions/aspects. For example, for restaurants users will no longer rate the “food”, “decor” and “service”.
  • Google will show just one overall score (they used an algorithm to translate the food/decor/service scores into a blended overall score).

To the dismay of many, Google replaced the yellow stars with the Zagat system in May, 2012 when Google rolled Places pages into Plus. It was clear from August of last year that Google was testing a return to the 5 Star system and they were never removed from local AdWords display.

The current iteration of stars appear to be universally red and it seems that they will roll out to all properties over the next few months. The new “Places” results that were spotted earlier will apparently be the results seen when visited from the new Maps interface.