[accordionclown]

rest (restructured text) has been used for python documentation for a very long time. so -- especially for that particular usage -- it's much more functional and clearly documented and consistent and free of edge-cases than (the far-too-numerous flavors of) markdown.

on the negative side, there aren't many quality authoring-tools for rest.

markdown has a very high profile. but it's questionable whether it deserves it. (i wouldn't say that it doesn't. but i wouldn't say that it does, either.)

another option you could look at is asciidoc. it isn't clearly better or worse than those other two systems, but it is different, and you might end up liking it better. (or you might not.)

light-markup systems are much like static blog systems. there's a lot of them, but it's hard to decide among them, and many people end up inventing their own variant that serves their own individual use-cases.