As an alternative, you could give people free copies of your ebook and ask them to review it. If its good you should trust them to write good reviews.
+1 I have to agree him. I think you'll get a better quality reviews which would be honest. My cousin is a author and wrote 2 fiction novels to put on amazon so I can of understand how tough it can be.
Mind sending me a link? I would like to check it out.