Many companies are using bloggers for feedback, as well as the promotion aspect. The feedback can be as valuable as a focus group, but less $$$$. There's a risk for the company, but that risk is minimal if you have a good product. There also is risk for the blogger -- being a pawn, poor credibility -- but as long as the blogger/reviewer is upfront if he/she is getting paid (other than the free product), again the risk is minimal.

I think if you focus on requesting product feedback in contacting bloggers, rather than asking for a published review, you'll get better results. It's human nature to want to be an expert, sought-after, needed, and asking for feedback plays into that. And, naturally, many will blog about the product and their feedback.
Mike

I do believe that it can be done right when receiving products or services to review for free.

There are a number of people that do surveys where this is the way companies receive their feedback.

When one reads a review, I think we do need to take into account that there may be a slight bias that is not intentional by the one doing the reviewing. With this said, I think that it is a good way to get input and build good relationships.