I'm about to migrate recipes content from hRecipe to Schema.org. Since many recipes are already ranked nicely on Google with the rich snippet, I would like to know if anyone had migrated before, and can tell me whether or not there's an adjustment period in which ranking and rich snippet change.
Thanks in advance for any advice!
You could keep the Microformats and use Schema.org (via Microdata and/or RDFa) in addition. The Microformat classes won’t hurt, and there might be consumers (like browser add-ons) that only understand Microformats.
That way there shouldn’t be any change in displaying the Rich Snippets (unless you have inconsistent annotations).
Adding Microdata/RDFa is mostly adding attributes to existing elements, and possibly adding meaningless div/span elements. So your actual content will stay untouched (mostly, at least), hence I wouldn’t expect any noticeable ranking difference.
