In my view the private reviews are not fair to sellers at all. If a buyer is really unhappy, they are going to leave a low rating even on public review anyway and if they are happy they will leave a good review. I don't see the point of private reviews when we have a public review already. Having two different reviews means psychologically the buyer might leave a different ( lower) rating thinking it is private anyway and it should be different from the public review. Just my two cents.