It's finally here! Use the Check for Update item in MacJournal or head to Mariner to get the final release. The major new features with 5.2 are support for the iPhone version, downloads of more than 50 entries for LiveJournal, automatic backups for non-main documents, better UI for setting default font and color, fixes for Quick Note with Spaces, improved compatibility with non-Blogger Atom servers, and, as always, fixes for MobileMe syncing.
If you have a question or an issue, please consider visiting the support forum or using the "Report an issue" item in the Help menu in MacJournal. Thanks!