This beta is primarily to fix issues with the HTML exporters as well as QuickLook preview support as it uses the dynamic HTML exporter. We've also included a hanger fix that could be triggered from mouse input events and fixed the issue with short and long date formats in the QuickLook previews.
Instead of listing off all the exporter changes on the blog, here's some example comparison images:
You will find the download links and detailed release notes here. Enjoy!