Good question. The answer is no, non whatsoever, so I'll tell ya how I draw such a conclusion. Some of this almost made it into other replies but I wanted to keep them short and to the point so... here it is now.
First I assume that we're all after the most accurate sound reproduction possible, not some euphonic garble that lays the same veil of effects over everything played, but actual, accurate re production.
One thing I can tell you is that bad class d amplifiers can sound amusing, for a short time! Having odd properties of being euphonic in odd ways. For example, like modulating the signal with RF noise giving you a perception of wider soundstage because in effect it's like adding some level of reverb ... creating it's own "ambience" which is not that of the recording..while the true ambient carrying micro detail is blurred out in the mess. That's an effect you can't turn off when you get sick of it.
Taking pre filter feedback with a peaky frequency response introducing gobs of second hardmonic distortion, and then "correcting" for that wicked peaking response with a bastard of a zobel network that starts to roll off at 10khz if not sooner leaving with you a rolled off high end, horrible group phase delay, but it wouldn't even be stable without it, stands every chance of taking out your speaker, and every chance of blowing up if the speaker cables get ripped out..... sound quality becomes a distant goal in the face of that, and more importantly, a distant memory. "but non of our customers complain..."
So to listen to them initially can be pleasing, because that kind of mess is "different", perhaps even to those with "trained ears", however the longer you endure them the more tired you become of it, physically, emotionally..draaaaaining. You'll eventually reach a point where you're so sick and tired of it that you can't bring yourself to turn it on again and then it's time for dumping it on ebay.
What was euphonic eventually manifests itself as serious flaws. How fast that happens will depend on your taste of music and the like. It may take hours, may take months, but eventually you're left to wonder why everything you play on it tends to sound the same, why the ambience you used to enjoy in your old favorites is somehow... not there? Why everything played has the same character, like listening to the same recording over and over. Once you get there... ah.. "I think I like my tube amp better so.. ".
Consider that if you do a little diggin, you'll find statements by nufarce saying such things like "we chose high EMI over some type of distortion.. it sounded better with high EMI", and then see above. I've been around this long enough to know who's who and what's what. Like you don't need experience behind the wheel to know that a town bus isn't going to beat an F1 in a race, subjectiveness aside, one has a clear technological advantage over the other and no level of marketing BS, awards, patents, reviews, changes that.
In order to get accurate sound, an amp has to have certain characteristics in order to be neutral and transparent. If you were to compare some of the very best high end amps out there, well regarded for excellent sound quality despite their class or compisition, you'd see they all share certain characteristics.
You don't get that when THD is strongly frequency dependant, that's heavy coloration, nor do you get that with a load dependant frequency response, far from transparent, nor do you get that with an amp that doesn't even have a flat frequency response across the audio band, especially when combined with the above two frequency dependant characteristics. This is largely what rules out the others, even before EMI becomes a factor with them.
BTW I made a mistake, some IcePower modules do actually have SMPS as well, much of their newer line includes a smps, but I don't know which ones the bell canto uses, it may or may not have them. The thing with Icepower stuff is that back in the day loooong ago when they first came to pass, they were cutting edge revolutionary, and then they got outdone right quick, and never stepped up to the plate with a real amp. As recent as last summer, they "updated" their line (sprinkles)... and it still shows all the same poor characteristics because the core of their design (modulator) remains unchanged.
Then there's the whole EMI thing, which completely rules out the one, and is a slight thorn in the other, but no where near as bad. The only one that meets every criteria is the UCD based amplifier. That is why I can recommend the CIA of the three, without ever having heard any of them.
As an example of this, I'll link you to an article from an italien magazin that did extensive testing on a variety of such amplifiers, including nufarce, one that contains the IcePower motor drivers (rotel), flying mole, Tripath based Sonic Impact (see what a joke that is.. bbbrrrrr), a high end class A/B amp with the correct characteristics for high end accurate sound reproduction (the other rotel), and a Hypex UCD.
You don't even need to understand the language (I don't), just study the graphs very carefully. You'll see they even included a really good comparison of them all with a variety of real world speaker loads. Even a quick glance at page 6 should make this all painfully obvious who the pretenders are and who's the real deal. If they all shared proper characteristics, theeen maybe we could get into the subjective discussion side of things, but as it stands, there's no point in that whatsoever.
http://www.hypex.nl/docs/classeD_394_lores.pdf
Having said that:
I do not vouche for the CIA monoblock sound quality (subjectively), nor can I comment on it (never heard them myself), merely the underlaying technology within, that I am extremely familiar with in every respect.
The earlier UCD modules like CIA uses had a few areas that needed massaging in order to unlock their full potential in sound quality. Hypex told everyone what those areas were, but the final, subjective result, would be a product of the guys skill, experience and preferences doing the work.
Whatever Dusty did with those amps, unless he screwed them up royally and I doubt he'd gone and done that, they will behave with all the characteristics of a proper amplifier because it is intrinsic to their very design topology, because as I said before, they were designed to be high end amps from the ground up.
So the little things like choice of caps (subjective to a large degree), op amp, resistors in feedback path, input stage regulation, etc, are all that it comes down to. It can still make a drastic difference. That's why I can't at all comment on the sound itself of the CIA stuff. If you trust Dusty's experience and reputation you shouldn't have a thing to worry about. Consider that your risk factor, but I can and do assure you that the underlaying technology is the real deal, robust as all hell, risk free, and with all the right characteristics that make up an accurate, high end amplifier, that your other choices lack entirely.
I do have extensive first hand and ear experience with those modules, even having designed my own. I've owned 180ST's, 400AD's, modified the hell out of both of them, now using 400HG (absurd sound quality, needs no modifying), 700's that are collecting dust until I design a proper SMPS for them, my homebrew ~35 watt UCD amp wired in point to point, designed by me with a few tips from the inventor, based off the patent, copied by all. I did that without even owning a scope, (retarded, desperate), and a big box of junk parts, and it works great, but obviously doens't meet low EMI criteria. It was done for learning though, not the best sound ever, and well, cuz I'm poor, and wanted a good amp.
All my UCD modules that I didn't design myself were free samples except for the 700 which was a gift from someone that let it sit in their drawer for a year and decided it was too big a project. I run them off an unregulated RAW DC supply of my own making that is extremely high end, but just in stereo to keep costs down.
I have most of all the parts here I need to turn my 400HG's into monoblocks though, just need to gather some odds and ends.
I also own a newclassd amp hand assembled prototype, sent to me for evaluating (also free), which is a complete joke as per the first few paragraphs in this reply, and emulates a jet engine extremely well, when it's not slamming my speakers with 40Vdc+ because something went wrong or .. just its extremely poor transient response at power up.
I can turn my radio on from across the room and tell you exactly what the switching frequency is by tuning into the noise on it and listening to the amp hunt for steady state, that it never seems to reach. Put two abortions like that side by side and the heterodyning/beat frequencies between them will be such that while listening to audio, you'll swear there's a flock of birds chirping at your window.
Just to say if you think free samples might sway my opinion, secure my friendship or loyalty.... nope!! Newclassd doesn't give me samples anymore, for which I am most grateful. I only have respect for good engineering, and good people who aren't con artists. I can, have, and will continue to cut the nuts off anything else, simply by conveying the truth about it.
So that's it, in a nutshell. You know where I come from and why I say what I say. You have all the info you need to make an educated purchase with the least risk of wasting your money on pure garbage. If your subjective ear doesn't meet with Dusty's, (which is a risk you have with any of the amps anyway, except for nufarce which lets you return them within a month..[not really long enough to grow weary of the euphonic RF modulating noise]..) and you don't tremble at the sight of a soldering iron or SMD components, you might even email me for the odd tip, but I wouldn't jump into that boat too quickly.
Cheers,
Chris