Notebooks app on the iPad makes a very nice markdown viewer

GBC

With the caveat that in some cases I'm now taking slightly longer notes to the atomic ones we often discuss on here - my notes now are often small passages of writing on a topic (with links to more atomic notes where appropriate), I'm very much enjoying the Notebooks app as a viewer of such notes. It presents the notes in something that does indeed feel a bit more of a notebook (you can swipe between pages (that is, move to the next note) and it has a nice clean appearance, and obviously the links work (although there's no 'back' function to return to where you've just come from). If you've put headers in your notes (again, this is something I'm using for longer notes and probably not so much part of ZK) you can easily make a table of contents for a document (only at the document level, not from a collection of documents)

You can also edit markdown, but I think I prefer 1writer for such things.