Looking for best streamer without DAC under $3500

+2 for LUMIN U1 mini. Made my Ayre QB-9 DSD DAC sound much clearer than USB from a music server.  

Why do you need a streamer like Aurlaic or a Lumin? Any 1 of these streamers mentioned above are just computers with some proprietary software. A few years back, I used the typical setup, a dedicated Auralic Aries hooked up to my external dac using USB and a few of the typical tweaks to usb. At the time, Aurlaic sounded better than the Lumin or Aurender streamers and had the best software on the iPad to control the Aries. 
I got rid of all that USB crap, the auralic Aries, and the external dac and went with a network attached dac, Roon running on a dedicated Mac mini, and the SQ is much better and the whole setup is much simpler.
My takeaways were: never use a computer/streamer in the audio room, never use USB if you want good sq, and get the best dac you can afford that uses ethernet or I2S interfaces.

My 2 cents......

Simaudio Moon Mind 2

https://simaudio.com/en/product/mind2-network-player/?v=7516fd43adaa

or

Bryston BDP-3

https://bryston.com/digital-audio/bdp3/

These retail at around 4K, but you can find them in your price range from several retailers.
I am currently using the Bryston (connected with AES). You can also find some pretty good deals on used v1 and v2 from time to time. I absolutely love the thing.  I also use Roon exclusively, so I can't speak to usefulness of the the Moon or Bryston app.

I have heard and liked the LUMIN U1 mini, I also love the look of it, my only issue with it was the switched power supply, so I never went down that road.

@rbstenho, what setup did you go to that utilizes I2S? I have a terminator with I2S and am looking for a streamer that utilizes I2S.

+1 rbstehno

Magna Mano Ultra i2s into DirectStream DAC.
You can run any music service you want.
If you just want to add Spotify a Blu N100 toslink out for $300 is plenty. Just ignore the WiFi and built in DAC - both shitty.