Two more places to comment, as if we haven't got enough already: Google Places and on your Google+ page.
Today, we’re introducing Reviews in Google Places for Business. Now you can learn what your customers are saying about your business on Google and across the web, in one place. If you have a verified business listing, you will now see your customer ratings and reviews in the easy-to-use review inbox. Google Adds Reviews In Google Places [googleandyourbusiness.blogspot.com]
And if you feel your business deserves more good reviews, or if you are missing feedback on your work, all you need to do now is to encourage your customers to post reviews on your Google+ page.