NewsFox works like Mozilla's Thunderbird, using an email-like interface to view RSS feeds. The left is your entire list of RSS Feeds, where the top right section is the list of posts of that feed selected on the left and the bottom pane is used for details of the feed item selected in the list pane.
Most RSS Readers have an OPML import/export feature, which NewsFox does and handles even the largest OPML files (I tested this with my 200+ feeds). :-)
NewsFox uses the Sage parser engine to read and display the RSS files. NewsFox doesn't allow you to save enclosures as they are received through your feed. Since podcasting is a big deal nowadays, most RSS readers should include this as a fundamental feature.
The web site doesn't have enough documentation to talk about features or a getting started section.
If the feed has categories, NewsFox takes your feeds and organizes them automatically into those categories. For example, if you add Ajaxian (RSS: http://ajaxian.com/index.xml) to NewsFox, you'll notice that it will create one folder called Ajaxian and set up the categories underneath that folder. Nice feature. No fuss, no muss.
There are some features lacking in NewsFox, but if you are just beginning to work with RSS feeds, the familiar email interface is a great way look at RSS. If you are looking for something with a little more meat, look to either Wizz or Sage to satisfy your needs.