I'm pretty sure the people that say it doesn't haven't tried, at least in long auditions and/or with MQA DAC's or properly configured. Otherwise, we won't be reading all this hate.
I have two rather modest DAC's: A Chord 2Qute (about US$1300 in its time) and a Project Pre Box Digital S2 (MQA enabled; $500; I bought it specifically to try if hardware decoded MQA was in fact better). When playing non MQA files, the Chord sounds a little better (in fact, I think Chord sounds more harmonically rich than most DACs I've tried, dozens of them). The Project DAC ( ESS 9038-Q2M) while very pleasant, has a little thinner sound. When not listening MQA files, I prefer that sweetness of the Chord unit.
But when it comes to MQA files, the switch from the Chord to the Project (with the DAC properly configured in the pc to decode by hardware, not that obvious) is instantly noticeable, even with the Chord already playing MQA unfolded by software. The sound opens up, with an obviously deeper soundstage with sounds floating freely in a larger space; more focused instruments, more precisely localized, with finer micro-detail and palpability in each one. You can resolve with more clarity things like the individual voices of singers, or the same singer overdubbed in a slightly different pitch. Bass notes have a clearly better perceived decay (and that with a thinner sounding DAC); resonance of drums or lower piano notes are more noticeable. There is a wider dynamic range. Perhaps the most evident element (besides that killing 3dimensionality) is the explosiveness of sounds with quick transients, like when a drumstick hits the border of the tom-tom, or the upper part of a cymbal, for example. Some not quite radical changes in timbre. Back to the Chord and the soundstage collapses immediately (even through the Metas...), some of all that finesse gone.
That said, there are a few records where the difference is not that much (never heard one worse though); on the other hand there are others where the improvements are just shocking: a sense of realism, of the musicians being here that is just intoxicating. Btw, normally the higher the sampling, the better it sounds (2L recordings are exceptionally good). But even with 44.1K there is an clear improvement. I listen mostly jazz (from 50's onwards), classical (Beethoven to Bartok, some baroque), some electronic music (Hecker, Fennesz, Frost, Subotnick...). Occasionally some pop or classic rock. By far the most I listen is the ECM catalog that's almost completely available in MQA, and although many are only in 44.1K, even then when I compare them with my own CD's (my unit as a transport to the same DAC)... well... it is unfair, there is simply no comparison.
Some of these things may be noticeable because of some remasterizations available in MQA. It is a good question if those would be available if not for some protection for the publisher provided with MQA authentication. I don't have QoBuz, and to be honest, this same MQA passionate war is held in a local site in my country. Some users swear they don't hear differences between Tidal (192K) and HR files of QoBuz (also available there, same sampling); for example this was the comment of somebody about the "Ultimate Mix" of Lennon's first post-Beatles work, the beautiful "Plastic Ono Band". Perhaps, but all I can tell is that compared with my CD, the difference of this master is just light years.
