I downloaded the eval version and took a quick peek. It looks very iaWriter-like. It’s designed to be both a markdown editor and blog publisher, with support for Wordpress, Metaweblog API, Wordpress.com, Evernote, Blogger, Medium, and Tumblr. That last one gets my notice-I’m on Tumblr for linkblogging and other ephemera.
It seems to also support images, and some esoteric syntaxes like mermaid, viz, echarts, plantuml, sequence, flow that I’ve heard of but don’t use.