Earlier quoted context omitted.
Behind the scenes it's just running the usual packages for templates, markdown, minification etc., so for a fresh build it's about as fast as any typical grunt-based setup. But AFAICT it correctly detects when things don't need to be regenerated, so incremental builds are quite fast no matter what, unless you're editing templates. I recently converted my wordpress blog to hexo and blogged about it, if you're interest…
I like the full width code blocks you have in your design. Your site looks great, and all the better to know it's static!
The other nice thing about SSGs is emitting modern output (minified, etc). What comes out of wordpress is a horror show...