Every DAC I've owned has had a unique sonic signature, just like every analog source has sounded different.
In the R2R realm, I have a MHDT Labs Orchid and an Aqua La Voce S3. I had a Schiit multibit Bifrost for a while.
The Orchid is warm and "analog" sounding, but not the most detailed. The Aqua is very neutral sounding and more detailed. The Bifrost is great for its price, but had a bit of an "edge" to it I couldn't live with. I had a Mytek Liberty DAC and would choose any of the three I mentioned over it. It was very "digital" sounding and a bit bright to my ears.
My Teac NT-505 is not R2R, but strikes a nice balance between a bit of warmth, detail, and easy to listen to "analog" like sound.
I agree that it's more about the implementation than the technology and more about what sonic characteristics you desire.
If your ears and / or system aren't good enough to detect differences, then it doesn't really matter what you use.