The Next Stage in Composition -- McIlroy
Easy Style Sheets
Eliot Kimber of ISOGEN is a supporter, and says that…"creating an XSLT- and FO-based style sheet requires about one half the effort of creating the equivalent style sheet in a proprietary system. In addition, the incremental cost of adding new document types or new layouts to an existing family of document types or layouts goes down over time as you refine your XSLT code to be more modular, making it easier to add new functionality or new input or output choices. No other SGML- or XML-based composition system has this characteristic."
Adobe's Steven Deach suggests that XSL-FO could be best for documents such as financial-planning guides, owner and maintenance manuals, and legal agreements and contracts. It's difficult to see why anyone would embrace the complexity of FO for these technically straightforward applications, much less abandon a current system (of which there are many) in favor of FO.
As far as I can determine, the use of XSL-FO today is limited in the extreme. The sense I get from the several FO mail lists (including XSL-List@lists.mulberrytech.com, http://groups.yahoo.com/group/XSL-FO/, http://forum.java.sun.com/-forum.jsp?forum=34 and firstname.lastname@example.org) is that there are few users, and that those few users are either in early testing mode, or undertaking compositionally simple documents, such as forms. I know of a few publishers experimenting with FO pagination. I've seen little mention of cross-media applications.
There's little general knowledge to be gained from these mail lists, and not much sense that delaying an FO implementation will leave you very far behind the crowd.
Arguably the biggest potential for FO today is just creating better print output from Web browsers. As G. Ken Holman points out in his XSL-FO tutorial, "We often take the printed form of information for granted, yet how many of us are satisfied with the print-screen functionality from a Web browser? How many times have you printed a lengthy Web document and found the paginated result to be as easily navigated as the electronic original?. . . When we want to produce a paginated presentation of our XML information, we necessarily must offer a different set of navigation tools to the consumers of our documents. These navigational aids have been honed since bound books have been used: headers, footers, page numbers and page number citations are some of the characteristics of printed pages we use to find our way around a collection of fixed-sized folios of information."