Sophisticated and flexible, Open also works transparently with a variety of file formats, including Microsoft's.
Localizations of Open are available in 27 languages with more being constantly added by the community.
These differences are often significant: it was only with the latest version, for example, that the Mac version of Office was given Visual Basic for Applications (VBA) scripting capabilities after years of conspicuous absence.
Rumour has it that the next version of Office for Mac will bow early next year – prompting many to upgrade, no doubt, even as the memory of fades.
Written in C and with documented APIs licensed under the LGPL and SISSL Open Source licenses, Open allows any knowledgeable developer to benefit from the source.