I can see where the intent is, but if you launch 10 WP blogs for product reviews, you will have 10 sites to maintain and they are all simply PR0 blogs which carry very little authority or trust (regardless of the username/login/IP). If you maintain 1 site which you update regularly, it will be much easier to begin to rank for this site and earn a
PR (it's not a huge thing
PR, but just so you know from experience). You could then re-post the articles AFTER posting on your blog, to say 10 article sites (and track the links in Google's webmaster tools) and some of the articles to just 1 site. This will have the same effect, and you have the added bon us of the (possible) reprinting of those articles, so more links.
Just my opinion.