Google is the most important search engine because of its capability to return relevant search results. Negatively ranking a website would not change its relevancy so I don't think Google cares much about reviews. Ironically, Google likes links so negative reviews including a link to your website would help your Google ranking.
By Alain Houle, Alco Web Design LLC
All that said, people use the web when purchasing goods and services and positive reviews of your company might help build trust when comes time to make a purchasing decision. An easy way to do that is to add a testimonial page to your website with verifiable testimonies that potential customers could contact. Another option is to ask your satisfied customers to leave a positive review on your Facebook page or on the local search directories. This is more work for them and I am not sure how many would do it but asking costs nothing.
Please do not hesitate to contact Alco Web Design if you have any questions about website reviews.
Alain Houle, President
Alco Web Design LLC - http://www.alcowebdesign.com
N1337 Westgreen drive, Greenville Wisconsin 54942