I did a post on the unit and tube rolling in it.
The stock Shuguang tubes do not get enough credit--yours truly included. The beauty of the stock tubes is that they are very quiet and the preamp side of this unit needs that. If you aren't going to use it as a preamp you may not have to worry about quiet, non-microphonic as much.
I liked the Doge more than NAD M51, Border Patrol, Denefrips Ares. I haven't compared it head to head with any "Giants". All I know is that I love the sound.
When my reissue Gold Lion 12AT7s got noisy within 500 hours, I had trouble diagnosing where the hiss was coming from. I put the stock Shuguang's back in (they were next to new) and things quieted down.
I would have paid $2000-$3000 for this unit. The features are super.
When I built a Roon NUC server this summer, it instantly recognized the Doge 7 and they play really well together, even though the Doge is not "Roon" or MQA ready. It is DSD ready.
I saw a used one on US Audio Mart last week for $900 or so.