Last time I used it, all the reviews were from the actual customers. Companies cannot pay to be listed on it. But from what I read, once reviewed, they can purchase an "enhanced" listing?
BTW, once you join, make sure to go into the e-mail settings or else you will be bombarded by requests and prompts.
Older article from PC World, but basically lays out it and other alternatives.
I resigned up, as I need some tree work done that needs someone with the training and background to work with a particular species that can be tricky. Also some gutter work. Its been many years since I have engaged anyone in this area. And who know what else may pop up.
There are some bad reviews of Angieslist, will let you Google for those.
In the past I found my workers, through word of mouth. That is how I found my well man, pump man, concrete finisher guys, dozer man, electrician, heavy tractor repair, and so on. And these were long term guys who did a lot of different jobs for me at my Business. I went by 'gut' feeling after talking with them or looking at their work and was never disappointed.
Hope this helps!