Pros:

• It's exactly these type of apps which will help the mainstream adoption of the blockchain... very few people are bloggers.
• Yelp is corrupt as all hell... they continuously contact businesses to sell positive reviews... decentralization is the solution here (as long as people upvote truthful negative reviews as well.
• The reviews so far are fascinating posts by themselves.

Cons:

• The devs are working on it, but no English version is available yet.
• Not sure how the quality control works yet...