I spent a lot of money on Sonos boxes in order to set up a whole house audio system. I also use JRiver software. I bought the Jremote app in order to use it with the JRiver software, but the Jremote app also works with the Sonos boxes.
The Sonos app is still useful for many things, such as playing various music services like Songza and Pandora. When it comes to using Sonos with my nas library the Jremote app is much better than the Sonos app. One example is that the Jremote app can pull up all of the artwork and liner notes onto the iPad screen.
Moment65 about JRemote