The idea is very good.
Here are my comments so far:
- A few options might improve the reading experience, especially for those who - like me - are on the brink of needing bifocals. Things I would try are allowing users to reduce the contrast, change the font size (maybe even the font face), read in landscape mode.
- It took me a while to figure out the UI... tap to flip pages is similar enough to the kindle, but I don't hold a phone the same way. I would have expected flicks to work.
- Another reason why it took me a while to get the app to work is that the feedback doesn't help much: the previous page slides in from the right and multiple taps give the impression of not having any effect whatsoever (until the new page appears). Some kind of visual cue (an indeterminate progress bar, maybe?) would be better.
- Browsing large books is hopeless. I downloaded by accident the complete works of Shakespeare... getting to any specific play would take forever. Getting the ncx to work would be real nice.
A few bugs...
- The progress bar at the bottom doesn't seem to work correctly. I noticed a book where it would report almost 1/3 of the book by the time you are through the legal stuff.
- Sometimes, going back causes the text to be rendered as a title. Things go back to normal once you go over the title causing the issue, but that can take a while.
- One of the books had a TOC rendered as a table, which got entirely screwed up.
Sorry if that sounded like a rant, it wasn't meant to be.