Evan at Upscale provided great customer service when I felt the need for a high-end streamer and amicable outboard DAC -- even tho he turned out wrong about some details. My search quickly narrowed to Lumin and Aurender, and Evan talked me through the models and their suitability for my particular needs. When he championed Musical Fidelity M6s DAC, I remembered an unused trade credit from another merchant and obtained the DAC there. Well, turned out the Lumin worked only on the micro-USB input: frankly unlistenable on coax or optical; defective. Plus the MF had no AES input as Evan had thought. Those limitations, plus the fact I found the Lumin app rather maddening, led to an exchange (though I must say the LUMIN sound was incomparably pure, best streaming audio in my experience).
No trouble at all exchanging Lumin for Aurender, which outputs ONLY USB. For this connection you obviously want the best cable you can get. Evan had the mistaken impression that AQ's top-end USB 3.0 micro terminals were backward compatible with 2.0 in the MF, but nope. Anyhow, easy return. Now in the market for a more contemporary DAC, so I asked about the PrimaLuna tube version. Needless to say, Evan was a major advocate (though I found several unrelated reasons to rule it out).
Well, hyping your own gear is all part of the job description, so grain of salt on that. Customer service was first-rate, and the Aurender is staying indefinitely, so ++ there. Return customer discounts are available on SOME DACS sold by Upscale, but none of those ring my chimes. When time allows I'll audition Bricasti and such. Still, Upscale will stay on my "reasonable candidates" list, albeit in the "proceed with caution" section like 99% of other merchants.