When comparing Vienna vs NewsBlur, the Slant community recommends Vienna for most people. In the question“What are the best RSS readers for Mac OS X?” Vienna is ranked 4th while NewsBlur is ranked 10th. The most important reason people chose Vienna is:
Vienna is an Open Source project. That means that every single detail of its implementation is freely available.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Open Source
Vienna is an Open Source project. That means that every single detail of its implementation is freely available.
Pro Great Interface
Pro Powerful keyboard navigation
There are easy to remember single keystrokes to scroll through a post, mark it a (un-) read etc.
Pro Recommended articles that improves over time
NewsBlur has a discovery algorithm that users can "train" to show stories they are interested in and hide ones they don't care about.
Pro Keyboard shortcuts for fast navigation
By default arrow keys and spacebar are used to quickly navigate stories, but they can be rebound for premium accounts.
Pro Multiple layout & style options
NewsBlur allows users to customize the font size, line spacing, story layout, and type faces.
Pro Fast to use
Very fast to navigate around the UI and load articles.
Pro View content the way it is originally displayed
NewsBlur offers an option of reading articles just like they are displayed on the original site.
Pro Organize feeds into folders
Feeds can be grouped into folders for easier management and to allow users to separate feeds for work, comics, research, etc.
Pro Share stories with comments
Burblog is a simple, customizable website for sharing stories with comments that people can subscribe to.
Pro Aggregates email newsletters
You can forward email newsletters to a user-specific email address to have them aggregated in your feed reader along with your RSS content.
Pro Free / Libre software
NewsBlur is FOSS, so it can be freely modified & redistributed.
Pro Freemium service
Free version has a limit of 64 sites. Upgrading to unlimited sites costs $1/month.
Cons
Con No longer functions as Apple blocks its launch for security reasons
This have been fixed.
Con Freemium
This service is free, but can cost up to $24 per year for premium users.
Con Can't have unread items older than a 14 days/month
This is a premium feature.