Actually, Amazon has rules about authors reviewing each other’s books because it can be taken as an attempt to influence competition! When I heard that I thought it was hilarious and ridiculous. Authors DEFINITELY don’t think of each other as competition. If someone writes something similar to me, chances are her audience is my audience! And readers don’t sit there going “well, I’m only ever going to read one fantasy novel, so if I buy hers, I’ll never buy yours!”
That’s . . . like . . . THE OPPOSITE of how it works.
Support fellow authors, folks.