Dave has created a desktop version of River5, called Electric River, which he has created using Electron. I have it running on my Macbook Air but when I copy one of my subscription OPML files it doesn't appear to be recognized. Additional tabs are not being created. 

I've added the RSS file for this blog to the feeds list, so let's see whether this post will appear in Electric River. UPDATE: This post did appear, almost immediately. Cool. 

BTW, I really like the icon Dave choose for the app. 

Another thing that I like is that Radio3 is integrated, which is how I add articles to read in Instapaper and Pocket. 

In terms of my personal reading and writing workflow, I prefer a server-based version of River that I can access on any device via a web browser. A desktop app works well for new users. The good thing is that the same code is portable between the desktop and server versions, so it is easy for Dave to provide for both user groups.