Update Mar-2018 - I'm going with Caret which is both a desktop markdown app, as well as an (unrelated) chromeOS app. I still like Atom, however, it's still great!
For Open Source, Atom is a great editor (Brackets is another). But there are still a few warts, and of course plugins must be used for full functionality. All can be installed with: > apm install APPNAME
apm install autosave apm install dash apm install language-latex apm install markdown-preview apm install meteor-api apm install meteor-helper apm install meteor-snippets apm install sort-lines apm install tree-ignore apm install wordcount
Note that for autosave, need to toggle it on in the settings For themes, I am going with the simple Atom Light UI and Solarized Light syntax. To open atom, do it from the command line, by cd-ing into a given directory, then invoking it with: > atom . This will support multiple windows/directories with open tabs. Another problem currently is with printing, but that we can work around by shoving things through pandoc in the meantime.