I had the opportunity to beta test this app and have been doing so for a while now. It has been in the App Store for a bit at $4.99. There is a lot to like about the app, including its export of Markdown text to HTML text with Smartypants formatting. The preview is also very nice and the app is incredibly robust and full featured for what it is.
Personally it isn’t right for me right now — where I think it may fit nicely is for students taking notes (at least I would have like it for that). ((Which also makes me wish I wrote in Markdown back in college.)) I could see myself as a student taking notes with the app and using the in-app browser to goof off when the professor goes on an annoying tangent. The extended keys on the keyboard would make for better and quicker note taking too.
I also have a lot of faith in this app’s future given the amount of features that are constantly being pushed to beta users — a sure sign of dedicated developers.