I have two Aurrender and have had the Grimm in my system, and listened to Linn in several systems. So… that kind of gives me a feel for things. I have not heard the Lumin… I had eliminated it via extensive research. I also owned a Aurlic Aries G2 for about a year… not in the same league.
I think I would put it this way, all are good at their respective prices… organized by best sounding first: Aurender N20, Grimm, Aurrender N200, Linn. Aurrender has the lower noise floor and a a more natural treble. It is important to have a DAC that is up to the task, so you can benefit fully from the sound quality of the streamer.