The thing that is so important about a user review is the concept of “Word of Mouth”. Back in the day people had to ask each other what they thought about certain goods or services, and sort of get a personal review to help you make your own informed decision. NOW, you can type in the name of what you are curious about, and you can find review after review.
How is this important? Relatively unknown businesses can gain LOTS of exposure through these reviews, AND the more reviews you have available, the more likely you are to reach an easy decision. So help a small business out, write them a review!