I have an upgraded 818v3 + 7200SE speakers, and own a 192k FLAC versions of 2L's Trondheim Mozart album. I've had the 192k files for a while and although not normally a huge classical listener, I love this recording.. listened to it many times..
After I upgraded my firmware last Friday and played the MQA sample, all I can say is that I immediately went and bought the rest of this album in MQA (and several others). I also have an upgraded Prime headphone amp at work and have been listening to various recordings over the past week with great delight.
With my 818/7200's I ran a few A/B comparisons of a particular solo on the first tune that starts at about 1:20 and goes to 1:50. I was playing the 192k file via async USB ("MHR 192k"), and my MQA file via Roon/ID41 ("MQA 352k").
I have to admit that I was completely smitten on first listen (and over and over about a dozen times

. The violin sounded so much more realistic to me with the MQA recording. The notes were cleaner, better defined. It was like I could hear the unique characteristics of the particular instrument -- not just the tune/sound itself.
The next day I sat down and compared again the MQA versus 192k versions of this solo with the intention of writing about it here, but had to admit to myself that I wasn't blown away by it. In fact I had a hard time really telling the difference, so I decided maybe I just tricked myself. So, I decided not to post my impression here.
Reading VirusKiller's post changed my mind, because I realized that my first listening experience was at a louder "realistic" volume while my second listening was quite muted (with kids running around the room). Perhaps it's just me getting old and losing my hearing, but I tend to agree that for me the differences seem much more discernible at higher volume.
For those who may also enjoy this recording, today I bought the Grieg/Mozart piano sonatas (vol 1 and 2) and am really liking these as well! Guess I'm just a Mozart nut =)