LaTeX really fails at "register-true" typesetting, though. You have to allow it to extend pages here or there by a line or be willing to fix many orphans and widows by hand. AFAIK, this has to do with the text flow algorithms which are paragraph-based and cannot do some global optimizations. (Correct me if I'm wrong, I'm not an expert.)
Btw, I cannot confirm the compile-time criticisms. A whole book takes just a few seconds on my machine for one run. I wonder what people are doing who get slow compile times.