Since 1 week I have been the happy new owner of a Holo Audio May level 2, and I thought it would be interesting to share how this dac has influenced my relationship with my Stealth.
For background, previously I used an RME ADI-2 Pro, in DSD mode using HQplayer with the Ferrum Oor or directly in balanced mode. I wasn't quite happy with the sound, lots of recordings sounded quite harsh and especially during busy passages I had the urge to turn the volume up to still make sense of what was going on, which was not good for my ears. Many people reported that the Stealth will do this and make you re-evaluate your music library. No big deal, I just switched to my other headphones for less than stellar recordings.
Within seconds of hearing the May I could hear the hype was justified and I was quite relieved that I hadn't just dropped 5 grand on an expensive room heater.
The separation and staging are sublime and a big step up from the RME. I can hear this clearly on the HEDDphone and the HD800 and even on the Sundara, but the differences are the biggest on the Stealth.
Curiously the soundstage differences between the Stealth and the HD800 (two opposites on the spectrum) have lessened considerably, I no longer feel the Stealth soundstage is lacking anything.
But on to the main point:
the number of recordings that sound bad on the Stealth have decreased by 99%. I don't know if the May is doing the world's subtlest DSP or what, but everything sounds good. On the RME I found myself gravitating towards well recorded acoustic guitar and small jazz ensembles, now even brickwalled pop songs sound enjoyable (with impactful bass nonetheless!).
I think this is a case of the Stealth suffering from its own success. It is so ruthlessly revealing that it will scale into the stratosphere with the rest of your gear. I was not a dac believer but I am now, and my brain is itching for a scientific explanation. My wallet is very much hoping that cables and power conditioning firmly remain snake oil.
Disclaimer: I am still very heavily suffering from new toy syndrome and honeymoon phase

If my views change in the future or become more nuanced be assured I will post an update.