I built a similar single-source publishing workflow to publish my books, but it's based around DocBook. I am very happy with DocBook because it has all the feat

I built a similar single-source publishing workflow to publish my books, but it's based around DocBook. I am very happy with DocBook because it has all the features I need for technical publishing (styling, indexing, cross-references, etc). For writing I use OxygenXML, which allows me to edit text without working with XML directly and -- crucially -- supports change tracking that makes working with editors/copyeditors a breeze. To get good results from FOP you really need to dig deep into the XSL stylesheets. The amount of customisation work is usually not that big, but the problem is that you need to learn a lot about the stylesheets to know how to make the changes. If you don't already know XSLT the learning curve can be steep. The change-build-test process is very slow, especially when you're essentially guessing where to make the changes. (Which, for me, happened most of the time.) I was happy with FOP, but eventually moved to a commercial product: 1) I wanted to use OpenType fonts, which generally offer better quality and support a wide range of languages, 2) full support for ligatures, 3) better handling of SVG illustrations (FOP's integration with Batik is clunky and makes it very difficult to use the same fonts as the main document), and 4) better indexes.