For over a year now I've championed Kingsoft Office Free 2012 as one of the top Microsoft Office alternatives for Windows, and with good reason: It's one of the best-looking clones out there, with superb file-compatibility to boot.
Yesterday, Kingsoft unveiled Office Free 2013 (Windows). (Please see below before you install it.) I'll go out on a limb and say it's now the single best free replacement for Microsoft Office, for a couple of very good reasons.
In case you're unfamiliar with it, Kingsoft Office includes three modules: Writer, Spreadsheets, and Presentations. Needless to say, these aim to take the place of Word, Excel, and PowerPoint. For the most part they do an impressive job -- starting with how they look.
Office Free 2012 borrowed heavily from the old Microsoft Office 2003 interface you see in most other clones: LibreOffice, OpenOffice, and so on. Kingsoft actually did offer a more Office 2007/2010-like "Ribbon" interface, but to get it you had to spring for Kingsoft Office Standard or Professional.
In Office Free 2013, you can choose between "2013 Elegant Black" and "2013 Water Blue," both of which do a fine Ribbon impression. It's not an exact replica, but it comes close -- to the point where I'd call this the most attractive Microsoft Office clone ever. (Interestingly, you can easily switch to "Classic Style" if you do prefer the more old-fashioned menu-style interface.)
Kingsoft's product also does something that has somehow still managed to elude Microsoft after all these years: tabbed documents. Instead of having to switch windows every time you want to switch between multiple open documents, you just switch tabs. Another very cool amenity: a paragraph-adjustment tool that lets you modify indent and line-spacing just by dragging handles.
As for compatibility, the suite had no problem opening the smattering of sample documents I threw at it, including those formatted as docx, xlsx, and pptx. However, I should note that it can't save to those formats, only the older doc, xls, and ppt. That may be a deal-breaker for some users.
Likewise, Office Free 2013 does lack a few of Microsoft Office's more advanced features, most notably Outlook and any kind of cloud integration. But that's true of nearly all the other freebies as well. If you need Outlook, well, there's always Outlook.com.
To get the program, you'll need to download and run CNET's software installer.
Important: When you get to Step 2, be sure to choose Custom Setup, then clear the check box next to "Install toolbar etc. etc." In Step 3, be sure to click "Decline."
Kingsoft Office Free 2013 is almost too good to be true. I suspect that for most users, it will handle most word-processing, spreadsheet, and presentation needs -- all for a price that's impossible to beat.
That said, if you've found something the suite can't do -- or can't do well -- tell me about it in the comments.