Doesn't sound like it'll work as expected. I figure people would only rate it either 1 or 5 stars as they do most places with a 5 star rating system. Plus, you'd have review bombers, where people can purposely hit a RP with tons of 1 star reviews for XX reason. If you need an example just look to any company that had made the news in a bad way rather than a good way, and view their yelp reviews, facebook reviews, etc..