I use both languages and have considered Markdown. reStructuredText has suited me better for technical writing (especially programming).
Just wanted to chime in and say CMake implements a subset of reStructuredText and Sphinx:
This is in addition to using it Sphinx for documentation.
There's nothing wrong with implementing reST-based idioms piece by piece. The real power of reST being pivoted toward technical writing as well as having standards, including a specification for implementing custom directives and how arguments are passed into them.
The thing to like is, after you understand how directives work, there's no surprises. Sphinx is a popular project that pulls in it's own directives on top of what reStructuredText has out of the box.