I have heard some webmasters accuse the larger review sites of "stealing" sales. The idea is that the surfer sees the site for the first time on one webmaster's site/freesite/blog whatever, then decides to check a good review site before buying. He gets to the review sites, get re-cookied and the review site gets the sale.

I guess that means that review sites are indeed more credible, and thus get much better conversions. As a paysite owner, by all means, definitely get reviews out there, but I would consider focusing on the big review sites, the ones with more traffic and more credibility (i.e. reputation/branding).