I've used it for auto generated diagrams of our code. Partly because it's what I know, partly because, surprisingly, there isn't anything free similar.

It's crashy for moderate sized graphs. And doesn't have quite enough layout and styling features. It's good enough but I'm on the lookout for something better.

I was thinking about writing a markdown extension that would render a code block into an image using this and this extra system dependency is also what turned me off. It's just an extra roadblock for users and whole block of extra instructions for each platform that users have to figure out. It would be better if it would just work out of the box.