Excellent article thanks for the info. So should I assume that a well built DAC even MQA non compliant will give me equal or better SQ than MQA??
MQA is lossy, so it can't give you better fidelity than high-res. However, it compresses only information that is above the highest frequencies you can hear and (arguably) also lower in level than the quietest sounds you can hear.
CD quality sound is a bit different in that it just doesn't contain frequencies higher than you can hear and (arguably) sounds lower in level than you can hear.
Therefore, IMHO, as long as files come from the same original master, there will be no audible difference between CD, MQA, and high-res.
CD is already (just) beyond the limits of human hearing, high-res includes additional content that is further beyond the limits of hearing, and MQA also contains that high-res content but compresses it meaning it is present but lossy. In any event, this content was never audible in the first place.
However, MQA does claim to do their own remasters on a lot of MQA releases. If that's the case, these may sound different from CD/high-res, but that's not because the format itself is any better or worse.
So I'd buy your DAC based on factors other than MQA-compatibility.