In the interest of disclosure, since you are giving away a product as well as reviewing it, what is your connection to the maker of this product? Do they provide you with free product to give out? Do you profit from people visiting your site as a result?

Making this sort of disclosure seems like a good overall policy, when you are hoping people will develop a trust in your reviews. I know it would help me. Consumer Reports built its reputation as an honest reviewer by completely avoiding entanglements between itself and whatever products they were testing. I trust them far more than other product reviewers as a result.