[borrowed from: http://www.cv.nrao.edu/~pmurphy/doc-interchange.shtml]
[...]

Pat Murphy

People who use both Word and WordPerfect will usually let you know in no uncertain terms that the big problem with the former is its lack of the "Reveal Codes" functionality. This means you cannot really see the structure of your document, and some of the hidden codes may make it unreadable in other word processing or translation programs. This functionality is made possible in WordPerfect because the foundation of their file format is solidly grounded in SGML (Standard Generalized Markup Language, the parent of HTML).

[...]
WordPerfect

I'm biased. I have believed for years that WordPerfect (WP) is a superior product to Word. Many of my colleagues who have used both concur. As alluded to above, Wordperfect has two good features going for it:

1. The ability to "Reveal Codes"; when you engage this function, the window splits in two with the bottom part showing the various codes (font changes, hard returns and page breaks, boxes, etc.) You can step through these, delete unwanted or unneeded codes, and gain much more control over your document. Often, such codes can be the root of many document interchange and formatting problems. AFAIK this function is not available in Word or OpenOffice/StarOffice, or if so, in an extremely diluted manner.
2. All versions of WordPerfect (starting with version 6) have the ability to read a document created in _any_ other WP version. For example, my copy of WordPerfect 7.0 (on Linux, of course; yes, I've kept this old version alive even on Red Hat 9!) can easily read a WP file generated by WordPerfect Office 2000. Some advanced features may not translate, but the program won't balk or crash, and will render the content accurately.

This word processor has some added advantages. Its ability to render complex formulae, while still second fiddle to the wonderful (and free) TeX and LaTeX markup languages, has still made it a favourite of many Scientists. And it does possess some crude typesetting features, such as the ability to manually insert ligatures (e.g., for ff, fi, fl, ffi, and ffl) and do hand-crafted kerning (minute adjustment of the "leading" [as in lead weights printers used to use] space between characters). And finally, it is not restricted to the Windows platform, and has been available for Linux since before 1997.

Alas, the temporary (and rather costly) purchase of a minority stake in Corel by Microsoft in the early 2000's had the unfortunate side effect of curtailing the availability of WordPerfect for Linux. Corel dumped its Linux OS business, and let the Linux version of WordPerfect die a sad death shortly afterwards. So while you can still find old versions of WP Office 2000 for Linux, getting these to work on modern Linux distributions is problematic (Corel used their own tweaked version of Wine (the WINdows Emulator for Linux), one that is incompatible with modern versions, including the Crossover version [http://www.codeweavers.com/]. One can hope, now that Corel is no longer under the thumb of Microsoft, that they may yet resurrect this useful package for Linux users, but other than a brief "test" re-release of WP version 8 for Linux (one that has stability problems in modern environments, in my experience) they have shown no interest thus far in doing so. At this point, despite the compelling "Reveal Codes" function, I've given up on Corel and now use OpenOffice instead. [...]