I have the newest Peachtree Audio DAC-iTx.
I too was surprised to find no review, and in fact no location to add it to my list of ownership items. I use the DAC exclusively for headphone listening, and would love to tell you how that is going. If you have specific questions let me know! It sits in my experimental rig where I frequently plug-in and un-plug new equipment.
When I first set it up, I listened to several different high-end ($1000 - $2000) disc players. But for each one, I listened and determined there was something I liked better about the original player's sound and did not much care for the DAC output. So I settled on an inexpensive Pioneer DV-C505 source, for which I probably paid $150 at a fire sale circa 2003. It is a 5-disc carousel DVD player, now used exclusively to spin RedBook discs.
In my most recent experiment, I used my Mac laptop as a media source. I tried direct USB into the Peachtree DAC. I also tried from the Toslink output of the Mac into the DAC. My favorite sound though was USB from Mac into a Meridian Explorer, Toslink from Explorer into Toslink input on the DAC-iTx, stereo cables from the DAC into headphone amp, and amp connected to headphones.
Though I like to experiment with my setup, I do not personally feel well-versed in DAC technology. I'll answer your specific questions, but I do not feel competent to write a full review. This is my only dedicated DAC purchase, and one of only three dedicated DAC that I have listened to in my past. I have another DAC in the form of an Oppo BDP-105. However I use only the USB interface, and output only to a stereo speaker system. A desktop Mac is connected via USB to Oppo, which feeds its analog cables directly to amplifier, which are then connected to stereo speakers.
Please let me know if there is anything I can do to help, which is slightly less than writing a full review