Ranked in these QuestionsQuestion Ranking
Pro Free and open source
Licensed under Apache License.
Pro Comprehensive suite of applications
Apache OpenOffice includes applications for word-processing, spreadsheets, presentations, and database management.
OpenOffice is available on Windows, Mac OS, and *nix systems.
OpenOffice is available in 170+ languages.
Pro Full compatibility with Microsoft
Fully compatible with Microsoft formats - from the oldest to the latest.
Con Dead project
The project looks dead. They can't close even serious security vulnerabilities. You might want to use Libreoffice instead.
Con Documentation is lacking
OpenOffice documentation is incomplete and language is highly technical.