DNS is something which should be easy to document by providing bunch of examples.
There isn't that many ways to configure it if you consider the variations you can do.
For some reason djbdns does not do this, it gives vague hints and makes you read 50 man pages followed by 100 blog post and 200 websites with obsolete/slightly relevant info on what you're trying to accomplish and if the position of the moon is decent, your tinkering will eventually work.
When you reach the "oh it works" phase, you follow "if it works, don't f**king touch it!" mantra and you're good.
I've tried going through the djbdns code to implement some changes and it's really well written in the sense that you can get grasp of what's going on in there quite fast.
The code is simple in a way which reminds me of some early cisco code I've seen for stuff like switches and routers.
Maybe the "competition" is so bad at doing the same thing because over-engineering?
If the documentation of djbdns would be in par with the code quality, I'd call it superb software. Now it's "I need the features it provides so I deal with the issues and use it"