Apache Open Office - Mac, Windows, Linux
Developed by Sun Microsystems, now owned by Apache.
As of Apr, 2015 it did not support XML.

LibreOffice - Mac, Windows, Linux
developed by some of the Open Office team after Sun was sold to Oracle in 2009.

www.freeoffice.com - Windows, Linux

WPS Office Mobile for iOS, Android, Linux, Windows

Google Docs - create and edit documents online, for free.

Amazon.com: Customer Reviews: Microsoft Office Home and Student 2013 rating 3.2 out of 5

Reviews:
LibreOffice 5.0 Review & Rating | PCMag.com 5.0
"LibreOffice is a long-standing open-source project based on the old OpenOffice suite, still being developed as Apache OpenOffice, but far behind LibreOffice in features and reliability. "

SoftMaker FreeOffice Review & Rating | PCMag.com 3.5

WPS Office: The best free office suite since Kingsoft - CNET
"Personally, I quit Microsoft Office earlier this year and haven't looked back. I've been using WPS Office (formerly Kingsoft Office) 2013 and greatly enjoying its modern interface. Indeed, though some folks are fans of freebie suites like LibreOffice and OpenOffice, I find those tools a bit dated-looking. Kingsoft -- sorry, WPS -- feels fresh and current, and obviously the developers are working to keep it that way."

Best Free Office Suite | Gizmo's Freeware
WPS Office Free (formerly Kingsoft Office) is ideal for those familiar with Microsoft Office 2003 prior to the creation of the 'ribbon' feature in 2007. It will let you feel perfectly at home.

Best free office suite | Top lists | Softonic
Kingsoft's WPS Office is simple office suite that just includes the bare essentials,is one of the best. It offers a much more modern interface than both OpenOffice and LibreOffice plus a ton of features in its free version.
LibreOffice design feels more cohesive and modern than OpenOffice.

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last updated 26 Jan  2016