I definitely like the way the hot-reloader works with Markdown. Looks very convenient for working on documentation heavy sites.
While hot-reloading is impressive for modifications new pages require a process restart. Which isn't so cool.
I can't figure out how a page's title is calculated. All I want to do is put the site name after the page name...
Gatsby allows you to create React components in a page which is definitely going to be useful for some kinds of client-side helper apps.