I'm extremely picky, even anal, about placing textures on terrains. I hand paint every square inch so every texture is right where I want it. I don't do MA terrains though, which are much larger. I couldn't imagine doing it all by hand to make it perfect. The farmland on steep hillsides (even almost-sheer cliffs) thing has always drove me crazy though.
My current project:

It's all a matter of how much time the builder wants to spend looking at every sq. mile of his terrain and/or how picky he wants to be.