Well, a couple of factors are relevant: (1) digital equipment depreciates faster than most, if not all, other types of audio. That is working against you. (2) you have no sales feedback, so that is going to scare off some potential buyers, especially since this component is expensive. (3) Aesthetix digital, while fairly well-regarded, has never quite attained "flavor of the month" status and the Stereophile review was a bit lukewarm, especially regarding JA's measurements. The biggest positive is that these pieces don't come up for sale used often, so there might be a bit of a scarcity premium.
Be sure to post plenty of pictures, the serial number, the name of the dealer from whom you purchased it, and any other proof that you own it and are a trustworthy recipient of blind faith in a somewhat anonymous transaction. This is a ballpark guess: If it is in great condition and you are the first owner, you should be able to get about 60 percent of retail. Of course, you can list it at whatever price you want and then cut the price if there is no interest. I would not expect more, since in this price range, a lot of good DACs are available and many audiophiles are willing to pay retail to work with a dealer or to go direct to the manufacturers who allow customers to try before they buy.
If you are the second owner or there are other issues, expect less.
