This is a great question! I mention brand names to give credibility and context. I have owned a Wadia 16, then to an Oppo 205 with the modwright mod, to an entry Naim Streamer/DAC, to a DCS Bartok, to a pre-APEX DCS Vivaldi Stack, to a Lamizator Pacific, added a Mini DSP SHD for sub crossover, currently have a Lamizator Horizon and a Grimm Mu1 streamer.
I rapidily went forward through DACs starting 5 years ago. The changes in sound moving up DACs were smaller incremental improvments. Still the sound did not have "life" to it. It was interesting more for its resolution of details rather than it's engaging sound.
One day I decided to run my entire system through the DAC in the MiniDSP SHD, which has many functions including a DAC, but costs only $1400. Doing a shootout with a Vivaldi stack agaist a $1400 multi-tool sounds crazy, and it was...the sounds were dangerously close together. I immedialty decided to sell the DCS gear as sonically I saw the "Value" as a sham. I am not saying the MiniDSP beat the Vivaldi, I am saying it was very close and could not justifiy the price difference. After lots more research I bought a Lampizator Pacific DAC and ran it with my Grimm Mu1. The sound was different in a good way, moving away from the "generic" sound I had found so far. What I think the DCS APEX upgrade was attempting to address is to add "life" to an otherwise pretty lifeless anylitical sound. I am not knocking DCS as they make great gear and super solid software. The Vivaldi DAC was 10 year old technology when I owned it, impressive gear.
The Lampizator house sound has more "life" to it than I have found to date in other DACs. When the new Lampizator Horizon came out I took the trade in offer. When I heard the Horizon in my system I easily knew this was the best DAC I had heard to date. The best DAC developers are all focusing on getting "life" put back in the digital rendering. They are getting closer and closer. This is a very exciting time on this digital journey.
My parting message after that long write up, is that I found it very hard to sonically justify changing DACs in the 25K and lower region. I could hear differences, but kind of like testing powercords at a lower price point "I think it sounds better, but I'm not certain I like the trade offs". The sub 25K DACs all sound pretty good, but they typically lack that "life" that is so elusive. I am listening to as much "life" in my digital music as I can find and afford with the Grimm Mu1 streamer and Lampizator Horizon DAC.