I would like to point out that the Python port has become much more stable and a lot more feature-complete recently
And since Sphinx plays nicely with Python, Python natively supports docstrings (actual object attributes), and packages like Redbaron allow for parsing even comments for extended functionality (like documenting features), I'd vote for Sphinx. I know someone else mentioned it, but I haven't heard of Asciidoctor either, so I don't know how widely known it is.
Ultimately, however, either choice seems good to me.
> I'm looking for feedback and suggestions. Are there other tools we should be considering? What do you think of asciidoctor? Any other thoughts with regards to documenting b2?