fastest & efficent MarkDown in JavaScript

I'm looking for a JavaScript MarkDown (MD) engine, for both in-browser & server-side via node.js. Most of the time, the intended output will be HTML5 (though I may use MD for XML, PDF, & the various ePub formats; uncertain if direct MD to xxx-format or HTML to xxx-format would be best). Fast conversion of a large MD file would be best, but I'm also planning to use it on lower-end mobile phones, so memory usage is also to be considered.

I imagine there is JavaScript-MD experience out there that I can't find, tests people have run, etc. So far here is the information I have collected:

https://github.com/chjj/marked "Built for speed"

https://github.com/guybrush/showdown Older & no longer maintained

Other research, most older: What is the Best JQuery WYSIWYM Textile Editor?

Markdown to convert double asterisks to bold text in javascript

Javascript to convert Markdown/Textile to HTML (and, ideally, back to Markdown/Textile)

Is there any good Markdown Javascript library or control?

How would you go about parsing markdown?