Replacing Roon - What Should I get?

Occurs to me that premium audio hifi vendors would have little incentive to allow Roon to “sound best” on their hardware compared to their proprietary software.  
 

True. 
 

Also worth noting that no proprietary  high end hifi hardware is required to use Roon.  

I used a 2018 Mac Mini as a Roon core for quiet some time. Almost every iOS update caused issues. After a reboot it could take up to 30 minutes for the mac to see the attached music library and link it to roon. It was a major pain. It also turned out that sound quality improved when I introduced Nucleus One. Managing Roon on a headless mac mini is a bigger pain in a butt than managing it thru Roon nucleus as well. But in general you’re correct. 

I use roon on a separate Linux server with plenty of cooling and, for Roon, plenty of CPU horsepower. 

One thing I've learned to be suspicious of over the years is little appliances without enough cooling.  This may get worse over time, but essentialy the CPUs in them get overheated and start to malfunction until they cool down.  This has happened to me a lot with home Wifi routers.  The combination of network throughput and encryption ends up pushing them to the very edge of their temperature envelope. 

In these cases the solution is a fan.  I'm not saying you should permanently put a desktop fan on your Roon, but worth doing as an experiment. This may be more necessary when upsampling and conversion to DSD or vice-versa is happening, or with lots of DSP features being used, or simultaneous streams.  

If you have a Roon appliance serving as your core, and it tends to go south after x number of minutes, try putting a fan on it.  

I haven't used one so this is just my understanding - but the Nucleus devices don't have a particularly useful way to track resource usage like RAM and CPU, do they?  That makes troubleshooting more difficult...but hey it does obscure what Roon does to grind itself to instability! 

OP

You might this thread of interest. The thread compares sound quality when controlling streaming using Qoboz Connect to Aurender  Conductor and a couple of other options. 

After few days with jplay I’ve experienced, on multiple occasions, a music stream would stop, requiring play button to be hit again to resume. Limited features added to this issue and the only thing that’s left is slightly better sound quality than Roon. I’ve also heard several tracks where I couldn’t tell the difference, several where I preferred roon as the recording was pretty hot for jplay. But in most cases it sounds excellent. It’s a shame that it has glitches.