LibreOffice 5.1 arrives at a curious time. The Document Foundation recently announced a Web-based version of LibreOffice, raising the question of whether a desktop version will matter in the long run.
But in the short run, the desktop version definitely still matters. Many of the new features in LibreOffice 5.1 could as easily be added to the Web version. But the one that counts most in the desktop version -- performance -- continues to improve, a sign that little energy has been diverted from desktop's development.
Most of the recent revisions of the application have focused on modernizing the legacy OpenOffice codebase. The payoff has been faster boot speeds and better management of large documents. My standard test for such items, an 800-page Word (.docx) document, still takes more time to open and navigate through than it does in Word, but it's significantly faster and less buggy than it used to be in LibreOffice.
The "reorganized user interface" in this version isn't that different from previous editions; there's nothing here like the tabbed interface now common in Microsoft apps, for instance. Most of the changes amount to reorganizing a few toolbar buttons to show up by default, and a new menu entry for each app type -- Styles in Writer, Sheet in Calc, and so on -- provides explicit access to functions that were previously more buried.
Version 5.1 preserves the pop-out sidebar that provides quick access to document formatting and navigation. Across all the LibreOffice apps, it provides useful features that change based on context (a master pages overview for Impress, an object properties pane in Draw, and so on).
Most of the genuinely new features are minor ones aimed at removing what could be called "paper cut" pain points -- unpleasant little annoyances rather than total deal-killers. The Hide Whitespace option in Writer, for instance, removes the jarring gaps between pages, so it's easier to scroll through a long document without feeling like you're being interrupted. This brings the default editing mode closer to a proper draft mode I always felt was missing from LibreOffice. Web View comes close, but at the cost of the page number counter not working correctly.
Integration with several online document services, including Google Drive and Microsoft OneDrive, is another nod to the importance of online components to desktop software. While I had no trouble opening Google Docs documents directly, I couldn't save changes back to them -- not even if they were created as ODF files first, then uploaded.
A smattering of changes have also landed in the suite's other applications, such as statistical regression functions in Calc and appealing slide transitions for Impress presentations. Note that the latter's availability may be limited by your system's GPU; you might have to force-whitelist the GPU to make them accessible.
LibreOffice has always been a fine way to rescue documents stuck in aging, legacy file formats. Version 5.1 continues the tradition and adds document conversion modules for version 6 of Apple's Keynote presentation program, the long-discontinued Microsoft Write (eclipsed by WordPad), and files for Gnumeric (a still-extant FOSS spreadsheet application).