This is interesting article which describes what are the signs of fake reviews and how to recognize a real review.

Recommend to read if you are buying services online:

1. Are there lots of oddly similar reviews? It should be a red flag if you notice a similarity in the reviews across several websites.

Reading through reviews, you might notice a whole set that use similar word groupings and writing style. This often means the reviewers are either copying information or that the reviews were all written by the same person.

2. Are the reviewers all very new? Watch out for reviews from new accounts. Some of the reviews should be from long-standing members of the site.

You might find the person has reviewed hundreds of websites, which gives them more credibility than someone who’s only reviewed one site.

3. Is the review non-factual or overly factual? Facts are important in a review; don’t trust a review if facts or actionable information is light on the ground.

Similarly, a review that gives no personal opinion at all may well be a fake – and in any case, it’s not a great deal of help.

4. Can you only find very few reviews? In this case, it’s probably best to give any suspicious website a miss.