You can add any feed, but not more than 3 feeds can be added in the RSS Follower at the same time.
This package is perfect if you read a few feeds.
(Available from the Mac App Store)
You can add a lot of feeds. In fact, you can add all the feeds that you read, and even more. Also you can use Share or Mark via Sidebar.
This package is perfect for bloggers, journalists, PR experts and all the people who read a wide variety of feeds for a job, hobbies or you just like to know about everything that's around you.
(Available as In-App Purchase for RSS Follower)