Product reviews help common people lookup and see what are advantages and short comings of the product. But i have seen quite a lot of them biased. One such example being movie reviews, its alll hyped and tampered with. Be it movies or products/services, that kind of trust and credibility is need of the hour. There is no guarantee to see and find out if its being rigged. So a better model will be to allow reviews with good and bad points. Allow users to speak up with proof if good features are indeed hyped or to provide a proof which shows its indeed bad feature. As proper proofs come into play, there may be clearcut credibility in the process