I prefer to use UML as an output language, never input. It's good to come to foreign codebase and generate visual presentations of its hierarchy and flow graphs

I prefer to use UML as an output language, never input. It's good to come to foreign codebase and generate visual presentations of its hierarchy and flow graphs. As an input language, created by hand? No, not really. It's mostly something for java/.net architecture astronauts: often used only once, to generate the cruft that will be the project directory hierarchy, but it's brittle and grows quickly out of touch with code & documentation.