I'm a long-time fan of Chord DACs. I bought a DAC64 in 2006, and I've owned almost every model since. There's a distinctive family 'sound' (or lack thereof) consistent throughout the lineage. My experience is that Chord is not being disingenuous when they claim that the later/cheaper models improve upon the older/more expensive models. In other words, there seem to be genuine subjective gains from scaling the decoding algorithms as technology advancements permit FPGA chips which offer greater computing power and efficiency. Those gains can more than offset the disadvantage the cheaper models have in specification elsewhere in the circuit.
Of those I've owned, this would be my overall order of preference:
1 - Hugo 2
2 - QBD76 HD / HDSD
3 - Hugo / 2Qute
4 - DAC64 MkII
5 - Qute EX
The DAC64 & Qute HD/EX were near indistinguishable on an A/B comparison in my system (even with the buffer fully engaged on the DAC64). The same goes for the Hugo/2Qute (and rightly so). The QBD76 stands out a little from the rest. It's a bit more full bodied and smoother than the Hugo/2Qute, but equally resolving and engaging.
I think the Hugo2 (and presumably the Qutest) is another step forward, and it's the best of those I've owned. The DAVE is probably better still, but I'm not interested at the price.
As a point of note on the Coral series (DAC64/QBD76/DAVE) vs the Chordette/Hugo models. The balanced outputs of the DAC64 & QBD76 are desirable, but IME the 6V XLR output can over-drive the input stage of many preamplifiers, and even when it doesn't, it doesn't sound any better than the SE outputs. So, although I use a fully balanced system, I wasn't at all concerned about the sacrifice of balanced connectivity when switching from the QBD76 HDSD to the Hugo 2.