It has a new, modern-looking interface with options to change the skin color. You can also customize some hotkeys and the toolbar at your convenience. This will help you get the job done faster. You can also customize preferences, like security and updates.
It has a powerful PDF-to-text converter, which lets you view nothing but text (no images or forms), search within a document, select, copy-paste to clipboard, highlight, and even save the document to a TXT file.
The installation comes with the Ask.com toolbar for your browser. Fortunately, you can uncheck it before it installs, which I recommend because of some privacy issues related to it.
It has a lot of helpful tools and fully customizable interface. Since the addition of the Undo and Redo features a few versions back, it has experienced some important changes and it continues to improve. The security is an important thing developers have in mind as well as the resources it consumes. All in all, it's a great alternative to Adobe Reader.