Use of XSL-FO, CSS3 instead of CSS2 to create Paginated documents like PDF?
Updated 01.10.2015
I used to do CSS to PDF (wkhtmltopdf) and XSL-FO to PDF and I prefer CSS, but there are lots of issues with it. IMO the best CSS/HTML to PDF renderer is wkhtmltopdf, but it has tons of problems like print-quality material issues, page breaking issues, CMYK coloring, exact positioning and fullscreen rendering.
Requirements like "move that box 1.8mm to the right and up so that it touches the top of the paper" and "we need the last page to be a 100% wide marginless table" are both quite doable in XSL-FO but in CSS it is too frightening to even consider. In some cases CSS just doesn't cut it as good enough software to render it doesn't exist even if the tags do. Even wkhtmltopdf (0.11, not sure about later) uses XSLT when rendering the TOC and doesn't really support @page.
I can't speak for PrinceXML as although it looks great I know in advance that the price tag would be impossible so it's not an option - I suspect this is true for a lot of developers and companies.
If there was better software to do the rendering and more user I really do think CSS would be a better option usually as it's so much nicer to write (both css and the source (x)html) and there are tons of editors out there. It's a bit like the old Linux vs Windows debate - IMO Linux is nicer to use but lacks the software, existing expertise and support that is often required.
And to echo the comments, source material is always an issue with CSS. CSS for XML is a bit uncharted territory and just about everything everywhere is XML. Unfortunately. I have a severe dislike for XML even though it's practically much more usable than (X)HTML.
One possible reason for banking on CSS rather than XSL-FO in the future is that the XML Print and Page Layout Working Group at W3C is no longer active. There was not enough interest to sustain this working group. The group published an XSL 2.0 working draft in early 2012, but now it seems quite unlikely that an updated W3C recommendation will ever emerge.
There is a very recent thread on the XSL-List mailing list about the reasons for closing the working group and about the future of XSL-FO vs. CSS. See http://markmail.org/thread/65j2ah2kulcp35fm.
And by the way, even though this is an interesting topic, I'm not sure if the question is a good fit for Stack Overflow. IMHO, it is more of an open-ended invitation to discuss something rather than a question about a specific, practical, answerable problem.
Thanks all comments and answers!
Now, 2014, passed over 1.5 years of my post (May 17 '12), is time to consolidate: no answer was, for me, a "full answer", but all answers (see Nenotlep's and Alex's) contributed to form a big picture. My main motivation now, to consolidate, is the @mzjn's news (here) of 2013-11.
XSL-FO is officially dying
On Sat, 2013-11-02, Liam R. E. Quin wrote: "We have closed the Working Group because not enough people were taking part", W3C XML Activity Lead, about the failure of XSL-FO 2.0 continuity. (see a better copy here).
The last update for the Working Draft was in January 2012, and now confirmed: W3C stop developing XSL-2.
Why? It will be replaced by CSS3-page, see below.
PS: to discuss the "official statment", use https://stackoverflow.com/a/21345449/287948
CSS3 is officially growing
The standard CSS3-page is a draft, but many applications, like PrinceXML v9 and AntennaHouse Formatter v6 demonstrated that it is ready (!); and, the expected launch of HTML5 for 2014 is carrying along the forecast release CSS3.
So, I understand that for W3C, CSS3-page do all that we need to express good prints and good PDF.
Other motivations
One day, in a far future... PDF will dead — it is complex and is not part of the XML family or W3C investments —, and many claim that EPUB will replace it. This is another good motivation: tablet readers and PC browsers will print (HTML, XHTML and EPUB) as well as PDF. So PDF will be not necessary... And, for this day, the only standard need for, ex. Webkit printing project, will be the CSS3-page standard.
CSS3 is the key point in two strategic affairs: 1) to generate good PDF from XML or HTML contents; 2) to replace PDF.
NOTE: another 2014's updates for the links of the question: wkHtmlToPDF is now here. About "new texts", now we have many, see ex. Building Books with CSS3.
An updated answer for programmers, for this page's question, Why use XSL-FO instead of CSS2, for transform HTML into good PDF?
If you go further and implement a new system for XML-Publishing, there are no good reason to use XSL-FO. SUMMARIZING:
XSL-FO is a dead technology today, only used by niche companies, to give maintenance to legacy systems in big publishing companies, like Elsevier... Most writers/readers of Stackoverflow are from small and medium companies. Companies like O'Reilly Media, Inc. already use CSS3 for print.
CSS3 will replace CSS2, covering all gaps (and fears as @AlexS's) of CSS2.
today (2014), as you can check by Google or my links (see PrinceXML v9 and AntennaHouse Formatter v6), we have some good software to render content with CSS2 or CSS3.
as @bytebuster say, "CSS is much easier to develop" (and easier to learn!).
as I say above, CSS3 is not isolated, it is a piece of the "XML/HTML/SVG" family.
is much cheaper to develop "HTML+CSS templates" (hourly cost of a standard web designer doing a simple task), than "XSL-FO templates" (hourly cost of a rare professional in a complex task).
....
News...
Jan'2016, the definitive CSS3 standard is coming!
About W3C standards: the old "css-page" was replaced by "css-break", and "paged media" to "fragmentation"... Now it is a Candidate Recommendation, see https://www.w3.org/TR/css-break-3
Apr'2020, Blimey, +4 years and nothing!... Ok, need more tests
Total 8 years from question's post, and 4 years from "css-break-3 fineshed!" announcement ...
Chrome was the first to finesh in 2019 but some was wrong in test validation team of W3C, and in 2020 back... Now the status (in 23 tests) is:
- Chrome's Blink engine fail 1 test;
- Firefox's Gecko engine fail 3 tests.
The draft now is here and tests here.