I cannot comment on how the Terminator compares to the various other R2R DACs mentioned on this thread (Soekris 1561, Holo Audio Spring Kitsune Border Patrol SE) because I have had no experience with them other than that which I have read about them... and what I have read has been very positive indeed.
My experience with separate DACs, in my system, has been primarily with the, Metrum Octave Acoustics Octave which was supplanted by the Auralic Vega which, in turn, was supplanted by the AMR DP 777 SE.
The Octave was a very smooth sounding NOS DAC, but seemed to me to be a little boring musically. The Vega was more lively, but to my ears always seemed to have digital glare.
The DP 777 SE's output is tube implemented and it seemed to completely do away with any glare while retaining a lively musical presentation. I was very happy with it... very analogue sounding and never fatiguing.
Why then did I decide to buy a Terminator? Because I heard one. I live in Italy and there was one ''on tour'' here. I put my name on the list and has the privilege of being able to audition it for 10 days in my home, in my system. When it arrived it had been already auditioned by others and was fully burned it (about 400 hours).
It took me only 3 days to decide that I wanted to own one.
To my ears, the Terminator offers me an experience of music that seems more ''real'' more ''authentic.''
My standard for judging the quality of a system is its ability to faithfully reproduce the sound of real, non amplified acoustic instruments... timbral accuracy, if you will. And the Terminator gives me that in spades. With the Terminator, instruments, vocals, etc. just seem so real and, as a result, the music for me is even more emotionally involving.
With respect to the many other parameters by which we judge our equipment... sound stage, holographic imagery, analogue sounding, PRAT, transients, decay, etc. there is not a big difference between the DP 777 SE and the Terminator. The Terminator is just as analogue sounding as the DP despite the fact that it does not employ tubes. To me, it also seems somewhat better with respect to transients and decay, which adds to the ''realistic sound of the instruments, but they are both good in that regard. Also, with respect to wide deep sound stage and holographic imaging, they both excel at this.
Overall, I think that the Terminator's ability to reproduce dynamics is somewhat superior to that of the AMR, especially macro-dynamic shifts.
But, oh that timbral/tonal accuracy. The AMR is good at it, but the Terminator is much better. And as I stated above, this makes for greater emotional connection to the music... at least for me.
So... more timbral accuracy, tonal density, powerful dynamics... these are the parameters in which the Terminator excels over the AMR DP 777 SE...
And this is why I decided to buy it.