The addition of fast resume support is a welcome addition to the the Kindle app, making the reading experience more convenient because the time taken to be able to resume reading after switching away from the app has been reduced (e.g. after taking a phone call, or replying to a message). The Kindle app was already reasonably good in this area, but even a few seconds saving is worthwhile.
The update also fixes the bug that could see some books loading blank pages and also update the Kindle Store links to the latest versions. Amazon's Kindle app is almost certainly the most popular way to read eBooks on a Windows Phone device, thanks to its strong cross platform support, competitive book pricing, and large catalogue.
Nokia Reading does provide an alternative option, but lacks the scale and reach of the Amazon platform, something that has only been compounded by a lack of promotion from Nokia. Other options come in the form of a number of third party eBook readers, but none are able to match the book buying convenience of Amazon Kindle.
Windows Phone Store description:
Read eBooks on your Windows Phone 8, including thousands of free Kindle books.
The Kindle reading app puts over a million* eBooks at your fingertips—and you don't need to own a Kindle to use it. Choose from over a million Kindle books from the Kindle Store, including New York Times® best sellers and new releases. Amazon Whispersync technology automatically syncs your eBooks across apps, so you can start reading a book on your Windows Phone 8, and pick up where you left off on another device with the Kindle app installed.
Amazon Kindle is a free download from the Windows Phone Store.