I suppose it depends who you ask. Do editors prefer entertaining reviews to help sell issues? Certainly authors and publishers hope for fair reviews - and reviews that promote the book rather than the reviewer. And readers - what do they want? An indication about the content, quality and value for money.
And what about the reviewers? What do they want? Well, my top priority is being able to sleep at night. So fairness and honesty-without-unkindness are my major concerns. And if the book has a pronounced style, I might emulate that in the tone of the review.
Over to you. What do you think?