I use Yelp a lot to get some feed back on a restaurant. You have to take each review with a grain of salt as there is little consistency in each person's rating system. Typically you will find some reviews at 2 stars and some at 5 stars. However if all reviews are low/bad it does ring the warning bells. You can have a bad experience even at an excellent restaurant. Another problem is that many people will only post a bad review. They never get around to writing about their positive experience. I tend to also at other reviews posted by the reviewer to see if they are posting fair reviews or tend to be biased on way or the other. Still, any information is better than none. If you do not agree with the reviews posted, you can write your own.