Aurender N20 or A15

After many loops through the Aurender product selector, and paying attention to what I am willing to spend, I have landed at a likely choice between the N20 or A15.  For any who've had the chance to listen to these two critically with the same external DAC, can you ascribe any difference in sound quality?  

While I can certainly see that the N20 is a more flexible component in terms of digital connectivity, and has some additional hardware refinement, maybe the A15 is very very (i.e nearly indistinguishably) close to the same sound quality?  I realize I might or might not choose to use it's onboard DAC (my current DAC is the DA2 module installed in my C2700 preamp) depending on how it sounds, and indeed the DAC might be "wasted", but there is no N15...

Thanks for any first-hand advice,

Mark