Hi Opabin,
I too find the R2R DAC architecture more natural to listen to than sigma/delta or software implementations.
However, I have so far not been that enamored with the discrete resistor implementations with the exception of TotalDAC. Personally, I think the best digital sound comes from 2 things: 1) a very good R2R chip (either with over sampling (not upsampling) or non-oversampling) 2) IV conversion that is passive or with discrete transistor 3) tube or discrete class A transistor output stage and 4) massive robust powersupply.
There are some exceptions to that but they are few and far between...for me.
The first discrete R2R implementation as far as I am aware was by Accuphase in the early 90s. They then moved to using the BB PCM63K 20 bit chip (one of the absolute best) and in their top DACs like the DC-91 used multiple chips, like Aries Cerat does today (Accuphase called it MMB or multi-multibit). This lowers the noise floor and ups the dynamics considerably.
I don't think it is possible to get a discrete DAC to the level of precision of a laser trimmed chip like a BB PCM1704, which was the best measuring of all the IC based DAC chips from the 80s and 90s. Probably the most loved ones though are the AD1865N, which is used by Aries Cerat and Audio Note among others, the Philips TD-1541 and the BB PCM63K. IMO, these will all outperform a discrete DAC if implemented in ways described above.
As to Sigma/Delta. The Lampizator implementations are very good and arguably more "airy" and resolved; however, that doesn't necessarily make them sound more "real". Recent DACs that use top AKM chips are also very very good, like from Metronome and Ayon.
That said, I still strongly prefer a good R2R DAC implementation using IC chips. A friend of mine recently brought over an Abbas DAC that uses the old Philips TD-1541 16bit chip. This sounded wonderful...plenty of resolution and lovely tone and huge dynamics. The Aries Cerat DACs sound soemwhat more neutral than this but you still know it is a tube R2R DAC and the dynamics and soundstage are huge. More detailed and resolved than the Abbas DAC as well. The AC DACs have a very "grounded" sound where there is this sensation of an ultra stable foundation upon which the music is built and organized...it all makes sense together. It is not as "airy" and extended as a Lampizator DAC and some people prefer that.