Technical writers have been asking this question to themselves for the good part of the last 15 years.
Short answer is this – if you’re writing a short memo, letter, or document, MS Word would be fine. No problem.
But if you are writing a book, something over 50 pages and with figures, tables, footers, index, references, multi-level paragraph numbering, you’d better stick with FrameMaker.
I’ve seen 50 pages documents going haywire with MS Word. And I’ve also seen 1,000 page manuals perfectly structured when written in FrameMaker.
It all comes down to this: FrameMaker is a very mature and solid product that can handle structural complexity very well. You can have as many nested numbered lists as you like without any strange errors in your numbering system. With Word, on the other hand, you’d better keep your numbering scheme to as few levels as possible.
FrameMaker also has a great Book compilation functionality that works every time and creates perfect books out of individual chapters. Word also has a similar outlining and book-compilation functionality that works erratically.
FrameMaker is also a great single-sourcing platform with its own built-in XML engine. It works very well with WebWorks to compile help files out of source document files. The standard edition of WebWorks comes with FrameMaker. MS Word can also be used for single-sourcing purposes but only with the help of additional third-party plug-ins and programs.
Another FrameMaker feature I like is the easy way in which you can insert running headers and footers, the kind you’d see in a phone book or catalog. There is no easy straightforward way to insert such “runners” in Word.
