MacDown is a text editor specifically intended to support Markdown, a plain-text formatting syntax, with the objective of providing an easy-to-read markup. Although the editor can be used to write unformatted text, just as you would use any note-taking app, its real power comes from taking advantage of the benefits provided by Markdown.
The application has a very straightforward interface. Like many other editors of this type, it has two panels: one to write the code and the other to preview how it will ultimately appear on a browser. Fortunately, the welcome page is a sample document that allows familiarizing with the concept and potential of the tool. The good news is that it is possible to change the way the document is rendered thanks to its support of CSS.
It is good that you do not need to know everything about Markdown syntax. In this respect, there are shortcut buttons to perform common formatting operations, like indenting, switching styles, changing font types and inserting images. Likewise, you can get plenty of help from its autocomplete feature. Besides, it comes with syntax highlighting for several languages when you are writing code.
The app can export to HTML and PDF, which makes it useful as a converter from Markdown to these formats.
On the downside, MacDown is not as versatile and sophisticated as another available editor of this type. In this regard, the possibilities to customize it are limited. Similarly, it does not support extending its features, as some other tools do. Regrettably, it may use too much of your system resources, even for simple operations.
All in all, MacDown is great if you are taking your first steps with the Markdown language. Luckily, it is open-source and thus available for free. However, more demanding users should probably look somewhere else.