I have an all Benchmark stack, DAC3B | HPA4 | AHB2 x 2. I have yet to find anything that will replace it for my 2 channel Thiel CS3.7. Though I have had more expensive gear in recently, CODA CSiB and KRELL K-300i, I have always said I like the same music a little better on the BM stack.
The only time I had an issue with the BM stack is with my RAAL SR1a headphones. I am listening to them as I type this using HPA4 | AHB2 x 2 | Audio Mirror Tubadour III SE DAC to tame the RAAL’s ribbon.
The DAC3B was replaced by the tube DAC with the RAAL and that made things rather good. Though I will be improving things even further with the RAAL by using a CODA 07x preamp and a D-Sonic amp. So all my Benchmark gear is replaced with the RAAL. On my 2 channel the Benchmark gear cannot be beat. The BM stack does not work with all gear. For, example Paradigm Persona would be awful with my BM stack as is the RAAL.
I owned the Benchmark DAC1 and after a while I realized I hated the fatiguing nature of that DAC. I had to use a BAT VK-42 SE preamp to make the DAC1 listenable. The DAC3 is much more pleasant to listen to. It is also much better sounding when paired with the LA4 or HPA4 preamp. I have owned the DAC3 HGC and used it direct to a AHB2. The HPA4 I now have with the DAC3B is much better overall sound. Especially at low volume listening sessions.
I have used my Tubadour DAC with the HPA4 and AHB2s on my 2 channel and it is good but I like the DAC3B more in signal path for 2 channel. The Tubadour should be similar to the Pontus.
BTW - if you are in the USA get the DAC3 on a 30 day home trial from Benchmark and return it if you do not like it.