I have a Lumin U2 mini hooked up to a McIntosh C2700. I am using the DAC2 module. My only comparison is against a Mac Mini as Roon core/streamer that I original had connected to the C2700. The sound improvement with the Lumin was absolutely worth the money. I could not go back to using the Mac Mini to stream as I was doing before. I would not hesitate to invest in a better streamer.
I think the next step for me would be to get a standalone DAC instead of using the DAC2 module in the C2700. I am not certain which DAC to even consider at this point.