Pages.app. We paid a couple hundred bucks for a (well-regarded) local graphic designer to build a print template for us that included typography, they delivered it in Quark, and I ported it over to Pages.

For what it's worth, I edit text in a text editor (Emacs), then use Markdown to get it into something that's easy to paste into Pages.app. I've done long-form editing in Pages.app, and I don't love it, but it's far less painful than LaTeX.