I have a big problem with FeedWordPress (2012.1218 on WP 3.5.1). If I place posts in "review pending" state (instead of published) I get duplicates on every automatic update (if I update by clicking on the button I don't get duplicates).
If I delete the posts in "review pending" I still get duplicates on the next update. If I publish a post I won't get duplicates any more (but I'dont want to publish all syndicated posts).
Not all feeds are affected. An example is http://www.cvjm-blog.de/feed/?cat=13
This behavior is a big blocker for using the plugin.