This one is very different. The first thing you notice is the backlit screen, no more need for cases with built in lights, or external lighting. The next thing I noticed was the improved readability. A new font (bookery) that is much easier on the eyes. The 6" screen means it's easy to hold in one hand, and change pages by swiping my finger forward or back.
So, how does this tie in with Microcontrollers?
The complete collection is searchable, so all my Arduino, Raspberry Pi, Python, PHP, MySQL, etc. content is available at a few finger presses. Makes it easy to find what I need to make any new project.
There are other improvements, but these are the ones that stand out for me.
Coredy Kickstand Case Cover ($14) protects my Kindle well, has a built in stand and stylus, and automatically turns on my Kindle when I open it. Highly recommended.
Solar charge your kindle / tablet / cell phone - http://amzn.to/1EmP95b