WordStar beat the pants off of WordPerfect for technical layout and hackability when it came to printers and the like for rush documents. I used to mod WordStar to support printer escape sequences where there were none using a hex editor. That dated back to at least around 1985.
I still miss WordStar, its keycords (^K^B to begin a block), context menus and loads of other things outshone WordPerfect for technical writing. I wrote thousands of lines of DBase II/III and C using WordStar's text mode. Hell, even Brief (circa 1988) implemented the same keycords as WordStar, it was really popular with DOS app programmers back then (e.g. the Clipper season based releases before Clipper 5 arrived).
But then that was maybe the dev in me. WordStar was more versatile as a tool for both Word Processing and as a text editor. However WordPerfect was more loved by the non-technical writers and I can kinda see why, but I could never get my head around the function key sequences.
* caveats here being that I wasn't introduced to vi until 1987, just as I left college, and didn't have affordable access to unix until I stole a copy of SCO Unix for x86 around 1992.