I currently run an Amazon script on my site that provides a full catalog. On each product page is an iFrame with product reviews and ratings from the Amazon site.

If I were to switch to using merchant datafeeds (Amazon has short cookies and conversions are harder with that), I don't see that user reviews are present. My understanding is that having user reviews really does help make more sales.

What do you advise? Are reviews really a mover? Or is the switch to more merchants, or a mashup, to get a longer time frame for conversions and more customization worth the effort?