Use the "Check for Update" item in the MacJournal menu to get it, or visit http://marinersoftware.com/ to download directly.
The big goals with this release are performance and stability. Well, performance, stability, and export. Several bugs that could cause crashes are fixed, as well as issues that could prevent proper content searching. Search indexing should also be faster, as well as any other situation where you're loading a lot of entry text all at once (such as exporting). Multiple selection of entries should also be faster. Several issues with export have been fixed, including several file naming issues.
If you obtained MacJournal from the Mac App Store, you can get the update from the normal App Store update mechanism when Apple approves the update, which should be soon (judging from past experiences).
A word on localizations: unfortunately, they are still underway. We are working hard to update the localizations right now, but none of them are complete enough for this release. Once any of the localizations is ready, a new release will include them as soon as possible.