Silly question perhaps, but how would you currently suggest installing this theme?
Just by copying the source content into the build dir?
I've been copying the 'build' as the theme and adding the SCSS from source and compiling to style.css. That's been working well so far. I'm not involved in the project, But I already installed it and I update it occasionally from github.
I'm making a child theme based on 2012 beta. It's a moving target, I know.
I'd be leery of using anything in source. That may include incomplete code. The updates to build seem to be fine.
The CSS is incomplete and unrefined.. but since that's what I'm customizing anyway I decided to risk it.
I think they are doing a pretty good job at meeting the goal of this theme.
You can ignore the source directory, just use "build".