IMO the two most important factors in sound quality with regard to streaming has been the quality of the external DAC I have used and the quality of the original recording being streamed.
This strikes me as correct. Many people tout expensive streamers but what is really driving that? In other words, I'd like to know if those who advocate for more expensive streamers (such as @ghdprentice ) did careful streamer vs. streamer tests so that they were certain that the differences they heard were due to the streamer alone and not, e.g., to other factors such as the ones mentioned by @2psyop.
I posed this question -- roughly, "Is it the streamer or the DAC that makes the greatest sound quality difference?" -- and some very experienced members such as @jjss49 testified (if I remember correctly) that the streamer does make a difference but that is minimal compared to getting a good DAC. For both streamer and DAC, an external power supply also helps more than the differences delivered by the streamer alone.
Of course, the above is just about sound quality, not about interface, company reliability, etc.