Ranked in these QuestionsQuestion Ranking
Pro Free and open source
Licensed under Apache License.
OpenOffice is available on Windows, Mac OS, and *nix systems.
Pro Comprehensive suite of applications
Apache OpenOffice includes applications for word-processing, spreadsheets, presentations, and database management.
OpenOffice is available in 170+ languages.
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.