The problem with those rating sites is that they are of the opinion of those who wrote the ratings, meaning subjective data. Maybe you can think of a job you really enjoyed, but that you're coworker hated. It's that kind of idea. However, it can give you a general sense of what people are commenting about.
But if you really want to work somewhere I wouldn't just rely on a review by someone who worked in a different city and even country, and did a different job. Still go ahead and apply and find out more through the interview process.
I've used Glassdoor and Indeed. There are more review sites. You can try googling the name of the company you're interested in followed by employee reviews. ex. Hubpages employee reviews