Hi good, I downloaded the trial version of your app and I used it a little bit. Here's what I noticed.
Overall it's a well implemented app and I really love it. Congrats! However, I noticed when I opened a document in portrait orientation and called up the onscreen keyboard the page did not resize automatically. I had to zoom in (out? Always confuses me) to enlarge the page in order to be able to scroll up and get to the last line on the page.
I also like the drawing feature and how it retained its form even when I viewed the saved page in Ms. word, however, the inking lags heavily after a few words. In fact, after about five words, the strokes start going haywire and making phantom strokes and up to 10 words it becomes unusable. Now I understand it is a very fresh app and many apps at the first release had this problem even the stock Reader app, but it would be nice if you can work on the inking feature. To be sure, drawing is ok, but I guess users would also need the label or write something about their drawing.
Good job!