For ebook readers, there are many desktop readers to choose from. Some are limited to Windows or Mac OS while others support multiple platforms. The choice of desktop readers depends on your personal needs such as compatibility with your portable ebook reader and where you source your content. Two popular desktop readers are Adobe Digital Editions and Calibre. There’s really not much point in comparing these two readers as it’s not really a fair fight.
Adobe Digital Editions
The only things Adobe Digital Editions have going for it is a nice looking interface and the name Adobe behind it making it popular with many libraries for checking out digital books. Beyond that, it’s virtually voided of any real features. It’s a basic reader and contains no content management tools at all so since it’s free, use it to read and that’s about it.
Calibre is an open source ebook management, converter, and reader. The one thing I don’t like about it is that it’s ugly. The interface and icons look like something from the Windows ME era if iTunes had been available back then. If you use iTunes, you’ll be right at home using Calibre as it borrows its design heavily from iTunes. There’s a ton of features in the library management section including the ability to download book covers and meta data from several sources and synching to your ebook reader. Just like Adobe Digital Editions, you can read both epub and pdf books but Calibre also supports many other ebook formats including LRF, LIT, MOBI, TOPAZ, SNB, and comics. You can also use Calibre to convert these formats to epub but conversions are often hit or miss depending on the quality and layout of the original source material.
They are free so download both. Use Adobe Digital Editions for library checkouts and use Calibre to manage all your ebook content.