Evernote is gone. I'm using iA Writer now. It doesn’t have an API but it syncs with Dropbox (which does have an API) so I rewrote everything to work with Dropbox instead of Evernote.

I’m feeling good about iA Writer. The writing experience really is beautifully designed and working in markdown is a joy. Between iA Writer's tranquility, Dropbox's perfectly pleasant API and Markdown's impeccable simplicity I've been surrounded by nice things today.