well, if you're going to offer reviews, why not do it the right way? let users offer their own opinion as well as give a rating.
i'm not going to push my own software (just kidding, of course i am) i'm only going to steer you in the right direction...
if you register on my site you'll be alerted within a week or so about a new version of my Customer Review Manager. this one incorporates MySQL to store reviews and, to help you find what you're looking for, has the same kind of drill-down-the-categories page as on your site.
if you want to see how it works, you can download the flatfile version to get a feel for it. but if i were going to offer reviews i'd probably want to go the MySQL way. it's a lot more scalable and just feels solid under the hood.
you can see the flatfile version in action here (where someone is collecting reviews for MiniDisc T-Station equipment):
hint: try following the Decks
category to see a displayed review for the Sony item MDS-JA333ES
Stephen Carter, Random Mouse Software
Putting Customer Reviews On Your Site
U R L: www.randommouse.com