What makes a good review

What makes a good review?
A good review holds true to both honesty and respect. Attacking the work negatively is not a necessity however an explanation of how the reviewer sees and approaches the piece is. This can be done with varying degrees of tact however the best are subtle and kindhearted but firm. The reviewer should discuss physical, functional, and visceral properties. The reviewer if well versed in the area should bring in Historical references or touch on the contextual elements of the work. The best reviews are those that are easy to read and contain visual descriptions in order to convey the work to those that are not able to view the work in person.
Personal opinion is a valuable additive however it must be clear that it is only a single opinion of the work. The best type of review is one that is unbiased. The review should raise both good points and bad in order for it to be effect. Most importantly the review must be helpful and clear to the reader. A review that does not shed any light onto the subject that is being reviewed is a wasted effort.