I just added FioWriter to iTextEditors today. It’s a pretty great idea for an iPad text editor: it adds Command and Option keys to the keyboard, so anyone who’s used to standard OS X text editing operations can use it in a very familiar way.
FioWriter supports 30-some commands, including Ctrl-A, F, B, N, P and E (beginning of line, forward, backward, next line, previous line and end of line). Command-arrow keys all work, as well as Command-C, X and V for copy, cut and paste operations. You can select and navigate words and lines using the keys you’re already used to.
You can also quickly “go to line,” insert punctuation from an extra keyboard row and get definitions using the built-in dictionary. It has no Markdown-specific features, but it’s surprisingly easy to use if you’re already used to editing on a Mac.