If you are a legitimate niche expert, is it acceptable to send a private message or email to another niche expert asking them to review your site in post form on their blog? If the blog owner posts an unbiased (positive or negative) review about your blog or site on their own site, and includes a link back to your site, this would be counted as an editorial link (which is currently favored by Google for backlinks as these links are freely given). Do you believe this is a good option for building credible backlinks?