What is a best tone of a viewer of a book review

Tone means the authors attitude, or the feeling the author wants the overall mood of the passage or book to be. So, probably a positive tone.

Ok, first let's understand what tone actually means. In the dictionary it says that "Tone i s the way the author expresses his attitude through his writing." - YourDictonary

So, the tone of a viewer of a book review would be ... how they express the attitude through a book review! Then answer put the question this way.

"Which is the best tone?"