WordPerfect Version 8 for other platforms introduced a fair degree of support for SGML, which may make WordPerfect a natural fit when trying to translate documents from less portable formats as used by "famous Windows wordprocessing software..."
There are some library issues you may have when installing WordPerfect on newer Linux distributions due to it needing older libraries that are often no longer normally distributed. Rick Moen has been asked this enough times that it is becoming a WordPerfect on Linux FAQ.
After Angoss spun SmartWare off to a separate company, it seems to have languished, and you may find it challenging to actually obtain copies of the software...
This is one of the most sophisticated document design systems available anywhere; it is likely to be fairly complex to use, suited for complex publishing tasks.
In the end, Adobe didn't decide to continue to make it available.
Led 3.0 / LedIt! WordProcessor uses a multiplatform C++ class library called Led to implement "rich text widgets."