We often use static site generators as an internal tool, specifically for our living styleguides. We started with jekyll, but slowly moved over to Sculpin due to it's twig templating system.

The article points out alot of the great things that static sites offer like performance, security, and ease of use, but I really feel like static site's weaknesses are too big (right now) to be implemented for any (non-brochure) sites without a tech-savvy in house team.

Don't get me wrong, there are solutions out there to help you integrate forms, comments, editing interfaces, etc, but I really think they are best suited to small brochure-style sites or as internal tools. In my experience with implementing static sites, the lack of content editing was too complicated for a normal user, even with tools like prose.io, especially because your average editor needed someone tech savvy to generate/push/stage their changes for review and then to a live site.

I stumbled across staticgen.com while researching how to build a documentation site for work. While it does a great job of summarizing each tool, I couldn't find one that fit my needs perfectly. I stitched a generator together myself using Gulp, Markdown with YAML, and Handlebars templates. The whole thing was < 100 lines of code, so don't be afraid to just create your own static site generator if you don't like what you see. They aren't very complex.

For static website forms I would most definitely recommend https://fabform.io