Why I choose Middleman as static site builder for this site?
To be honest, I started first with Jekyll. It's most popular static site builder, made by Github, used for gh-pages and there is a lot tutorials and examples around. However, I didn't like feel that Jekyll gave me. Learning 'Liquid' templates was one of the steps I didn't like to take (after 10 years with RoR I prefer erb) and asset pipeline was too limited and unclear for my taste. There are few other things that I did not like, but those two are most important for me. I needed something less opinionated and more powerful. Also, it has to be written in Ruby, that way I can easily modify anything I don't like.
bundler and maintain your own
Middleman was right tool for me, at least for this task. Don't get me wrong, I can see myself using Jekyll for gh-pages in some projects, but not for this task. Building person website is something that takes time, changing it later even more. I want to spend that time using tools and technologies that work fast and well for me.