I too recently purchased the Pontus II. That DAC made the most improvement on my system.
The Cornwall IV was driven by Audio Research LS2+Parasound A21 with Node 2i. The the Willsenton R8 in place of ARC LS2+A21. It was better in most way. Then the Muzishare X9 SET yields the most listening pleasure for the types of music I prefer, vocal, jazz, acoustic instrument and blue.
When the Pontus II inserted into the system, wow. You can read all the praises from established reviewers for details. All my family members commended how musical sounding, life like sound with the Pontus II.