Jekyll in Ruby. This option is clearly the most popular, and it is the only one integrated into GitHub (builds are simpler). Even though I have no experience with Ruby, I wanted to choose this option initially. But then I discovered that Jekyll is not supported on Windows. Moreover, you cannot even use Ruby packages without downloading and installing 1GB Linux subsystem. It became apparent that this ecosystem does not care for Windows users (which I am one of).
Hexo in javascript. This option is less popular, but will probably rise in the nearest future. Using javascript for generating websites is a great idea, because any client-side code has to be in javascript anyway, so it is more convenient to use one language in both areas. I have suffered enough from javascript on my daily job, so I decided to avoid this too.
Pelican in Python. This option is probably even less popular than Hexo. Python is a great language for a variety of tasks, and my experience with it is strongly positive. It is very user-friendly, truly cross-platform, does not have tons of stupid legacy stuff like javascript.