When comparing RSSOwl vs Calibre, the Slant community recommends Calibre for most people. In the question“What are the best RSS readers for UNIX-like systems?” Calibre is ranked 4th while RSSOwl is ranked 10th. The most important reason people chose Calibre is:
Features include metadata editing and downloading, coverpage downloading., book tagging and categorization, webpage-to-ebook converter for popular websites, etc. Lots of plugins available to extend functionality.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Powerful book management software, very customizable and scriptable
Features include metadata editing and downloading, coverpage downloading., book tagging and categorization, webpage-to-ebook converter for popular websites, etc. Lots of plugins available to extend functionality.
Pro Cross-platform
Calibre is available for Linux, OS X, and Windows, 32-bit or 64-bit.
Pro Open Source
Pro Portable
Calibre has an optional portable build that can be stored on external media along with the users library. It can then be opened from the external media on any windows device.
Cons
Con Does not support TLS
The client is unable to read feeds using a secure connection with TLS.
Con Outdated
Hasn't seen any updates since 2014.
Con Average, non-power users might find the interface somewhat daunting
The interface, while functional is not the most attractive or intuitive which may put some people off and discourage their use.