When I read reviews, I look for the reviewer understanding Goethe's rules. Basically they have to answer three questions:
- What is this book trying to accomplish?
- How well did the book accomplish this aim?
- Was this an aim worth accomplishing?
Good review or bad, if it's structured this way, or at least contains this information, I can figure out if I'll like a book or not.
The problem is that most reviewers are utter shit at writing reviews.