The best solution for writing documentation
I tried many "Markdown Editors" and found them all lacking; neither the editors nor the markdown displays worked well. One of them requires your work to be on iCloud to render properly (whoever thought that was a god idea?). Here's the perfect solution: edit your markdown document with xcode (it has line numbers, and that makes moving around easier), and concurrently display it with Marked 2. Marked 2 updates whenever a save is done, and xcode saves the document every few minutes (assuming the option to do so is on). Also, it has a better rendering engine. It's truly a beautiful solution. Marked 2 is well worth the money. I just wish I had discovered this solution sooner.