I haven't tried the app (no Windows Phone), but according to the listing the features include:
- Pick up right where you left off. We’ll sync your bookmarks so you can keep reading across all your devices.
- Customize your reading experience. Enjoy crisp, clear text, in the size and style you prefer or try Night Mode for easier nighttime reading.
- Enjoy first chapter previews for thousands of select books and save them in your library.
- Quick access to your recent reads within the app and from Live tiles.
Have you tried the app? What did you think?