indeed they are very desirable... I have the 275 CE and for some time I had two of them; I sold the second one because i found they lost dynamic in mono... I know It sound silly as everybody seems to prefer them in mono... I can confirm aswell that the bass is definitly the "departement" that had to be improved... Listening to the mkIV version I found the bass punchier but not necessarily going lower.... For me the Bryston DAC before the C22 improved a lot of things in terms of details and bass. I recogn the C22 CE is not fantastic, I am not saying it s bad, but I am selling it right now because I have too much noise in XLR, because the volume incrementation is too coarse, and because many techs have told me it is not very reliable... Indeed its maker said somewhere he wasn't very pround of the C22 CE and did the C2200 right after... I assume the newer versions are better, but cannot afford it now....
Otherwide mids and highs are superb I think