With a large book being studied and many notes and highlights being made it seems to slow down actions and even crash the book occasionally. I thought this problem would go away with a new iPad and faster processor (air 2) but it has only improved slightly. It is understandable that such a powerful tool would be a little quirky and slow, and I'm sure the developers are working on getting it to run smoother.

Here is my suggestions:

1. I don't use the mind map or outline feature on large books at all. Perhaps if I could disable this feature, the book would run smoother not having to cut and paste in the background and store all that unnecessary information.

2. I would love more control of the margin size (would like to make it bigger) and font in it please!

Other than than that I think this is an incredible app that I enjoy using very much and I look forward to further improvements!