I have …
Including the little Meridian Explorer 2, Pro-Ject Pre-Box S2 Digital, the Mytek Brooklyn (and Brooklyn+) or Sony WM1Z.
As well as other units that require “software” to do the first unfold, and then handle the subsequent unfold and rendering in hardware, such as the AudioQuest Dragonflies and iFi Nano iDSD Black Label.
MQA content or not I did not care for either iteration of the Mytek Brooklyn. And at least with the first version, when I tried it, if you enabled MQA playback then it applied the MQA filters to ALL content, MQA or not, which did less than nice things to the end result. But that’s just me and if you’re interested in it then get an audition of it.
But, the first unfold is always done in software, even if it’s done within the DAC itself (it is often handled at the XMOS layer for USB DACs). The second unfold, done in the DAC, is also just algorithmic. The remainder of the rendering is a combination of software/hardware and is DAC-specific.
My ongoing experience with MQA remains that in the situations where it sounds better than simple Redbook PCM, on the same DAC, it is invariably down to different masters and not something that’s definitively-attributable to the MQA process or technology.