KiCad represents a huge percentage of the jobs that we see - most months, it's typically at the #2 or #3 spot. We figured that it was time to roll up our sleeves and write a guide about how to get perfect results with PCB:NG and KiCad. You can find our KiCad documentation in our help section.
We had to provide our guide in text and screenshot format - seems that there's no way to put all of this stuff into a master config file (although we're working on a solution to that). Nonetheless, we tried to be as exhaustive as possible. Follow our guide, and PCB:NG will not only work great with your output, but you'll probably sail through our DFM, too. (Of course, we'd love for folks to try it and show us if we're wrong about that).
We learned a lot about KiCad from writing the guide. It's a great package that has come a very long way, and we're very excited to help our users get the very best from KiCad every time. And if you're just hearing about PCB:NG for the first time, just a reminder that our beta is now open - feel free to hit our homepage and sign up for an account, OK?