Free app for Windows 7, 8, 10.
Ranked in these QuestionsQuestion Ranking
Pro It is much more lighter than Adobe Digital Editions, Calibre, etc
So, Icecream ebook reader will work faster.
Pro Pleasant reading experience
The app tracks how much of the book has been read, jumping between chapters or bookmarks can be done with a few clicks, and there's even a distraction-free mode that takes away all the interface and allows focusing on the book.
Pro Clean, customizable UI
The application has an easy to use and understand interface with important features such as search always within easy reach at the top.
The interface can also be customized to best suit wishes. For example, font size can be changed, there's choice between single and double column view when reading books, or table and bookshelf view when managing the library.