I've requested a limited number of reviews from friends and relatives with some good results, but have to add that when you do this, you find out who your real friends are. And I wonder what your thoughts are on this subject.
From one hat to another, I was trained to take hellacious critiques. I don't take them personal. A five star rating is great for promoting a book, but does nothing as far as advancing your skills. Most of my friends weren't capable of writing a review and my first came from associates. I was fortunate to have been given positive encouragement, but as long as the review isn't a personal attack, if it's less than spectacular use it for tuning your skill, if it's priceless, use it for promotion. You win either way.