First, a disclaimer: I don't have anything against quick or short reviews. My style requires a lot of time and I understand that few people want to spend their leisure writing an essay about their reaction to a book. What I dislike are reviews that sound more like advertisements than reviews.
When strolling through Amazon, I find reviews that disturb me. They're all composed of the same basic phrases: "couldn't put it down", "when's the next one", "recommend to all age groups/everyone/anyone that likes reading." In three paragraphs, it's easy to overlook them but when a review is one paragraph and made entirely of these phrases it raises a red flag. I think "Is this a paid review?" or "Did this person read the book?". When I gush about things, I go into detail. I avoid spoilers or warn of them, of course, but I want them to know exactly what I liked about a book so they will understand how great the story is and read it themselves. Generic reviews are a waste because they contain nothing specific about the story and so they could be copied and pasted any number of times.
A reviewer isn't doing an author any favors by turning their review into a endorsement. It sounds fake. Often times, it sounds cheesy. Posing questions that the novel 'answers' or saying that it bucks trends or some such; you don't sound like a reviewer you sound like a promoter. Nobody trusts a promoter because the promoter is biased. They're looking for an honest and informed opinion.
When I write a review it is long and it is thorough. If I dislike something about the book then I am sure to include it. I give A+s sparingly and even then I don't sound like "OMG! This book is awesome!!!!" It's a point of professionalism. Even for books that are not review requests, I follow the same format. Three sentences of generic praise may bolster the rank but it doesn't help the reader (at least, it doesn't help a reader like me) decide on whether or not to read the book.
I use bland language for this reason. Poetic lines are not professional because you sound like you're trying too hard to impress. By using such language you're trying to turn your review into something that is more than your personal opinion about a work; you're trying to make your review into a work itself. I find that silly and arrogant. Reviews are not supposed to be read like a book or a poem. They're supposed to inform a potential reader (and customer) about the book from the perspective of another reader and customer. Nobody cares how witty or enjoyable your reviews are because they're interested in whether or not you liked the book. (I recognize there are exceptions: newspaper columnists and bloggers etc can have fan followings of their own, but in that case, what they're reviewing is less important than the review itself.)
Genuine reviews are more effective promotions than promotions pretending to be reviews because the former has substance. It is unique. A promotion will not be unique and so has no substance. It's little more than literary junkfood.