My history with microformats on this blog has been long and mostly happy. I have great success with the hReview format, which is the one I use most frequently. I use it for book reviews, but it can be used for any type of product review.
I thought it might be nice to share the code. Not that I have anything different from what you might see at microformats.org, but I have adapted it a bit.
Here’s the code for the version I use now. It can be adapted to suit; just use the classes that you see for each element so it retains its microformat identity.
<div class="hreview" id="hreview-summary">
<span class="reviewer vcard">
<span class="fn">Reviewer: NAME HERE</span> </span>
<span class="type" style="display:none">product</span>
<img alt="photo of 'PRODUCT NAME'" src="PRODUCT PHOTO URL" class="photo" />
<a class="fn url" href="PRODUCT URL">PRODUCT NAME</a>
<p><abbr title="5" class="rating">★★★★★
WRITE REVIEW HERE
<p class="summary">Summary: SUMMARY</p>
I hand code in the number of stars I want to give using the character entity ★ because I haven’t had good luck with the autogenerated stars. Nor do they look good in Safari unless I use the character entity.
Google is very quick to pick up hReview information, which is why I’m so fond of it.