Stumbled upon this last week and used it in conjunction with FiftyThree's Paper app to create a pretty impressive prototype that I was able to view right on my device.

Bit more of a process when using Paper, as it only seems to be able to export an entire notebook in PDF, requiring me save pages individually in order to use them in the app. I seem to recall reading somewhere that MarvelApp was capable of dealing with PDFs, but I'm obviously mistaken. Would have been a nice feature, though I'm not sure if many others would benefit from such functionality.