It is a tricky job because the blurb writer wants to provide as much interesting information as possible about the author in one or two paragraphs. (Edinger House)

Secondly, copywriters are able to bring a freshness and vitality to a blurb that an editor or author who has been immersed for months and sometimes years in a book may find in short supply. (the penguin blog)

Look for the flow, the voice and the style of the blurb as well as length and language. (Associated Content)