I tried Hugo, Jekyll and Gatsby. Assuming that a static site is 95% likely a marketing (self, company or otherwise) site and a marketing site needs to impress, a static site generator should be first and foremost built from the requirements of frontend and not leave the user to "theme" some default HTML.

Gatsby is ridiculously fast (React based) and its plugin universe is full of all the common features you could ever need. It has built in 1-click service workers plugin for offline access, 1-click plugins for prefetching links you put on your page, auto-inlined-css (in v2), all kinds of markdown + fringe requirements like LaTex, video embedding, things like Call to Action plugins, MailChimp sign-up-here plugins etc. To get a feeling of the snappiness, check out their landing at https://www.gatsbyjs.org/ and their plugins here: https://www.gatsbyjs.org/plugins/ .

The community pushes and PRs at break neck speed every day and is super friendly - can definitely get the support you need. Lastly, it is a great way to "inverse learn React" if the objection is "Wow, I don't know enough React". React by itself is not that opinionated and Gatsby has enough good practices of putting together a React framework for you to use productively.

ps: the other frontend alternative would be vuepress, it should feel blazing fast too. Here's another article on why speed is so important: https://www.gatsbyjs.org/blog/2017-09-13-why-is-gatsby-so-fa...