RSS.app is the ideal tool for the casual RSS user. The app is almost invisible: It is embedded in the status menu and uses Mountain Lion’s Notification Center to alert you of new posts.
Neat idea, and a good way to get at your subscriptions that became inaccessible after Apple removed RSS support in Mountain Lion. However, Apple rejected it from the Mac App Store citing rule 2.8:
Apps that are not very useful or do not provide any lasting entertainment value may be rejected.