Discerning a difference between streamers is difficult...only me or common for all?

Roon Nucleus with a nice LPS?

If you're going to stick with the BlueSound Node, get yourself a Teddy Pardo power supply....you will notice an immediate and substantial improvement in the overall performance of of your Node....it elevates everything head and shoulders above the BlueSound without the Teddy Pardo power supply.  You will be very pleased.

The Teddy Pardo Power Supply is around $400.

Bluesound Node/Node-X/Node2i Upgrade Kit - Teddy Pardo Audio

My explorations over the years have led me to understand that differences between components can be minor but significant improvements could be had by spending attention (and money!) on modem, router, their power supplies, acoustic isolation, the quality of the AC going into the streamer and of course, connecting cables.

I use a 12V deep cycle battery to power my modem and router and another, via a pure sine wave inverter, to power my streamer/DAC. All connecting cables have RF filters installed.

My audio experience from Qobuz is delightfully musical: tirelessly detailed, spacious and very immediate, often sounding more ’live’ than Live...

@dogearedaudio 

One digital copy may exactly resemble another, but you still have to get that digital file from one place to another and then convert it to a convincing analog audio presentation.

The server just has to get the correct series of zeros and ones fed into the DAC with timing that's accurate enough to keep jitter induced noise and distortion to a minimum, assuming it's a synchronous connection. If it's asynchronous then it just needs to get the ones and zeros into the DACs buffer in a reasonably timely manner. A lot of server software can do that, with jitter noise well under 100dB below the signal. There may be something going on that's causing it to not deliver the correct stream of ones and zeros at least some of the time, or perhaps to be accidentally sending analog signal along with the stream of ones and zeros that somehow ends up causing noise in the analog output stage of the DAC, or causes the DAC to otherwise not function correctly. So I know there are sonic differences sometimes. I've experienced it. What I'm not getting a good explanation for is how the server software can possibly make the sound coming out of the DAC sound  different if the system is actually working to spec., and not having a problem that could be readily identified with a little analysis. At least the effect could be measured on the DAC output even if the root cause might be hard to track down.

 It's much harder to bring two different cartridge designs in to uniformity of output from the same groove. It's an electro-mechanical device, and making tiny mechanical things with various connected parts vibrate identically enough to be undistinguishable in sound output is more trying. I have seen some double blind tests that showed there are some cartridge designs that people struggled to tell apart, while others were successfully distinguished.