When it comes to SQ it's all about the precision of the clock, the cleanliness of the signal, and lowering the noise floor. Quieter is better.
Everything in your digital food chain counts. Router, switches, ethernet cabling, how your music is stored, the renderer, the DAC, and all cabling inbetween. A Bluesound Node 2i is a wonderful piece of kit for the money. It's enjoyable on its own. Add a better DAC and you can take it to another level. The Node beats a plain vanilla PC as a renderer because it is quieter, purpose built for the task. The better streamers are quieter still, better clocks and power supplies, but that refinement comes at a cost that we the customer must pay for. You can store your ripped CDs and downloads on any discoverable network share, but a purpose built storage device like an Innuos or Melco can yield whole other level of refinement. It's all a matter of how important it is to you and how much you are willing to pay for.