What are some alternatives?
When comparing Google Play Books and Cool Reader, you can also consider the following products
Amazon Kindle - Amazon Kindle software lets you read ebooks on your Kindle, iPhone, iPad, PC, Mac, BlackBerry, and...
FBReader - FBReader is an e-book reader for various platforms. Features:
calibre - Ebook manager, viewer & converter
Project Gutenberg - Project Gutenberg offers free ebooks to download.
Moon Reader - Innovative book reader with powerful controls & full functions
Kobo Books - Kobo Books is a best in the class eBooks and eReadering apps for many reasons.