Quad is in an alpha state: even if it persists in something like its current form, it will be changing and breaking your projects in all kinds of ways between now and when it is ready. But it probably will not persist in its current state; in an email newsletter from MB Type earlier this year, Matthew said “I have started a second prototype in Racket. I would like to build this into a working system and then port it to Chez Scheme for maximum speed.” So there are maybe one or two more separate alphas of Quad before it reaches the point where you would want to start relying on it. In the same newsletter, and elsewhere on this forum he said all of that development is predicated on getting funding to the tune of $100–300k.
Latex is ugly but fully cooked, and has simple macros for things like verso/recto layout, keyword indexes, footnotes and endnotes, that would be either impossible or completely manual in Quad right now. If I had to choose between the two for a project due in the next year, I’d pick Latex.
A non-ugly option that is worth looking into is SILE. SILE is under active development and accepts an XML-like syntax as input, which makes it easy to generate from Racket/Pollen.
I have yet to try it, but if you have the budget, you could also look into Prince XML, which purports to do quality PDF layout using HTML and CSS. A single desktop license is $500 USD.