Just to be clear, these are software programs that allow you to play music, but they don't provide the music. If you install Roon, you'll still need a source for music - either downloaded / ripped music files stored on your computer or a streaming service - I also like Qobuz.
I am just starting with this and so far I'm using just the Qobuz program (provided free but you need to pay the monthly subscription price to stream anything) running on my MacBook Pro laptop connected via USB and fiber link to the DAC in my C47. That works and sound really good to me but the Qobuz program is a PITA to use and the interface only runs on the computer - I cannot control the computer playback from, say, a smart phone. Also, though it sound great to me, multiple sources are telling me that connecting the computer directly to the DAC as I am will not sound as good as with an end-point device that improves clock jitter.
So I will likely upgrade to Roon and add some hardware devices. JRiver seems to be waning and Roon seems to be the better, much more functional choice.
So Roon would be a step up (and more money) for me to provide a much better user interface including remote control from devices other than the one actually streaming, provide much better meta-data (album cover art, liner notes and other info about what's being played) and support of multi-room, multi-system playback from a central server in your house. The Roon interface will allow you to play your own files stored on your computer or streaming playback from most of the streaming services all from the same user interface.
To support multi-room playback, you need endpoint devices and DACs in each system. As mentioned above, the end-point devices talk to your Roon server via your home network to get whatever digital music stream you want to play and stream it to the local DAC. They may also provide a better digital connection to your DAC wrt jitter and so better sound quality than with a direct computer connections.
The term jitter is not indicative of the sound it produces - the music will not sound jittery. Jitter refers to variations in the clock signal rate that the DAC uses to decide when to convert each sample to analog. The clock needs to run at a constant rate so that the samples are converted to analog at a constant and correct rate. Generally, the DAC gets or derives the clock signal from the digital data stream such that the endpoint device feeding your DAC can affect or reduce (improve) clock rate jitter.
So clock jitter does not manifest as jittery sound, it manifests as weird noise that can be measured. You won't hear jitter as noise or hiss either, more like it will obscure detail and quiet sounds in the music. The effect is relatively subtle and not readily apparent from listening without comparisons.
I am still researching Roon and associated hardware, including endpoints. I am a little reluctant to spend money on Roon and especially Roon-specific hardware as software programs come and go and digital formats change with time.
Note the spell checker keeps wanting to replace "Roon" with "Soon" or "Room" so hopefully a caught and corrected all of the unwanted corrections.
