Do also keep in mind that some of these refurb cameras are used in displays at conventions (these make up a majority as they are usually shipped as bulk directly to each convention and will not come with any boxes so afterwards they are visually checked/repaired/reboxed), minor factory testing issues and some camera complaint exchanges (returns) that are redone also at the factory. So most of the larger companies that sell these refurbs Cameta, B&H, Adorama are factory refurb cameras. Which will have a refurb factory warranty of usually 90 days (Some extended through store or 3rd party) as well.
If you stick with the larger companies to purchase one you should have no issues.