I have recently added product rich snippets to my product pages. They have since been cached, but the rich snippets are not showing in the serps yet. Is there some sort of rich snippet update I have to wait for or something? Or does it just take a bit of time?
whatson - Google has indicated in several ways that while markup is most likely necessary for the display of rich snippets, it is not sufficient. I'm thinking that authority, trust, and popularity signals are also being factored into the display.
Those comments will lead you also to a discussion about rich snippets, which includes some comments Matt Cutts made at Las Vegas PubCon in Oct 2013. Google is tightening up its criteria for displaying rich snippets, and Matt suggested that some websites would be losing them. Hard to say whether this is what's affecting you. I would work on improving the trust and authority factors I mention above.