This link may interest you.
http://www.digitaltrends.com/computing/best-microsoft-office-alternatives/
- Best overall: FreeOffice 2016
- Best features: LibreOffice
- Most similar to Word: WPS Office 2016
- Best for cloud collaboration: Google Docs
- Best for MacOS: iWork for Apple
1) The latest version of SoftMaker’s FreeOffice 2016 comes with full compatibility for DOC, DOX, XLS, XLSX, PPT, and PPT formats with a lot of work going into making them “loss free” – in other words, you won’t find any unexpected surprises when transferring these files into real Word programs.
2) [Mentioned above] Calc can read .xlsx files created with Microsoft Office 2007 for Windows or Microsoft Office 2008 for Mac OS X.
3) WPS’s Office alternative comes with Writer, Presentation, and Spreadsheet, all as closely cloned off the Microsoft versions as possible. All files you create with these apps will be fully compatible with Microsoft programs
4) I didn't see mention of compatibility for MS Office with Google Docs
5) iWork wasn’t originally designed for compatibility with Office Docs, but over time Apple has added more functionality. Now you can even import Microsoft files and edit them in Pages, Numbers or Keynote as needed, a huge advantage that makes iWork a perfect pick if you are working on a Mac in a sea of Windows users.