Of course you can change these default settings. They'll give you a choice of three basic fonts-Roman, Sans-Serif, and Typewriter while also allowing one to use special fonts for mathematics. They'll put chapter numbers on all your chapters and section numbers on all your sections. If you don't know what you're doing, LaTeX and ConTeXt will automatically produce a professional-looking book. The defaults are set for professional typesetting. They're free (although you can choose to spend as much money as you might wish on books). The source files never crash or become corrupted. They run reasonably well on the oldest, slowest computers. They run on Windows, Macintosh, and UNIX computers. They'll produce the most professional-looking books. Both are created on top of the older TeX typesetting language. LaTeX is a document markup language, while ConTeXt is more of a typesetting system. You know who Donald Knuth is (he's right up there with Einstein for hard-core computer science types).
