The foundation's press release begins with, "Berlin, February 7, 2013 – The Document Foundation announces LibreOffice 4.0, the free office suite the community has been dreaming of since 2001. LibreOffice 4.0 is the first release that reflects the objectives set by the community at the time of the announcement, in September 2010: a cleaner and leaner code base, an improved set of features, better interoperability, and a more diverse and inclusive ecosystem."
While LibreOffice isn't yet up to par with Microsoft Office, the open-source office suite features integration with several content/document management systems through the CMIS standard, better DOCX document support, improved importing of Microsoft Publisher documents, incremental UI improvements, a new widget layout technique for dialog windows, performance improvements to its spreadsheet program, first release of Impress Remote Control App for Android, and significant performance improvements when loading/saving many document types.
More details on what's new and different about LibreOffice 4.0 can be found at LibreOffice.org. There's more than 10,000 commits making up this new open-source office suite release. The new release also comes just days after the release of Calligra 2.6.