I don’t know much about the aurender, but i have streamed from itunes/bitperfect and (i cant recall the name) on my Macbook pro, and for years i have used Roon on a dedicated server. All three outperformed the CD player to the same DAC(s).
I will point out that Roon offers a number of advantages; since i have rarely used anything else in the last tow years, i can say how much they impact the sound - but the content difference is startling ( I have a love/hate relationship with Roon)
But here’s are the two things:
One -- there will be differences, based on implementation (hardware, powering, grounding, ...)
Two: on the other hand, if the software plays the music back bit perfect, you can get identical results.
Why? two critical factors in digital are magnitude and timing. Timing is the harder of the two since it is quasi analog. (read my blog on SonogyResearch if you want more). And timing is determined by the receiving DAC, but compromised by the player’s signal from which it must be derived. I admit there are some details deep down that i cannot explain. yet :-)