I've always thought 5 star rating systems were fundamentally flawed because they're based on the assumption that the same experience experienced by two different people will get the same star rating. For example, what might be a four star experience for me could be a two star experience for you.

Maybe it's just me, but I'd prefer a probability system such as up and down votes. If I see a restaurant has 100 "likes" and 10 "dislikes" it's probable that I'll also enjoy the place (given the fact I already know they're serving food and drinks I would normally enjoy).