Roon works seamlessly, easily and consistently. I couldn't say the same for any of the other applications.
As far as sound quality, I preferred Amarra, PureMusic and Audirvana on different days. There seemed to be no consistency. One day Audirvana sounded great. The next day Amarra or PureMusic sounded better.
Roon sounds tremendous.
Sometimes I find myself preferring the SQ of Audirvana, but not consistently. I'm not upsampling, just native rates, so its baffling that they sound different at all (2012 Mac Mini with Uptone JS-2 LPS).
For user experience and exploring music, Roon is streets ahead.
The Roon look and interface makes Audirvana look like something from the 90's (wish Damien would get rid of that lame 'galaxy' background and make it plain blue like the preferences window).