Music streamer with no DAC and no storage?

Something based on a Raspberry Pi?

Roon Nucleus. New $1400. No storage or DAC.

If you are looking for something simple to set up and use with USB output then the three top choices divided into two price categories for each company would be the Auralic Aries G1 or G2. the Lumin U1 Mini or U1 and the Innuous Zen Mk III or Zenith Mk III.  For each company the first choice is in the $2200 range and the second in the $4500 range.  Each is a reputable company with solid software and support. With the rest of your gear avoid these cheaper options unless streaming is just an afterthought.  

I have tried unsuccessfully with "just" streamers, Not only sound quality varies a lot but ease of use with the app. I have ended up, and I am currently happy with my Bryston bdp2 ( I have 2 of them!) and DCS upsampler (streamer included)
DCS do just a streamer (Network Bridge), which is one below the upsampler which is very good. In my view the only Naim product to compare is the top of range £10k + version (not the lower ones) but I don't think that gives such "value".
The bdp2 prices will have dropped to make it an absolute steal 2nd hand as the bdp3 is out and not a sonic improvement apparently.
I looked at the Bluesound and have been put off for reasons which escape me at the moment. From memory it was quality of sound and connectivity in my particular system.

Whilst writing I pondered over the use of Airplay suggested above, Airplay in Roon is far inferior  to normal wired ethernet so maybe the context I am missing on other products.