Hi ENIAC, your post could not be timelier. On Friday 11th, Marc Mickelson of The Audiobeat, posted his review of the Rowland M825 stereo amp, which sports those very class D NCore NC1200 modules that you have experienced in your system.
Marc's findings are based on prolonged use of the amp in his system,, which protracted for a number of months... Yes, I estimate the device to have been fully broken in.
He appears to concur with your opinion that appreciation of musical neutrality in high achieving class D amps may require a paradigmatic shift for some audio lovers, away from some much beloved traditional warm sound.
Amongst other things, he expresses the following thoughts in his conclusions...
"Such a peripheral line of reasoning underscores what is very best about the Model 825 -- and potentially any great piece of audio equipment: it makes you forget that you're listening to a complicated and expensive audio system. This is more than the ability to suspend disbelief; it's a disarming of critical faculties, even when you're trying to be critical and unravel what you're hearing. In my experience tubes do this more readily than solid state, and class D almost never does it. The Model 825 does it as a matter of course -- it can't not do it -- and it happens not because of one or two or three of the sonic traits I discuss above, but all of them, in their exact proportions. If the Model 825 were somehow more natural, bordering on romantic, or more round and rosy, especially through the mids, it would be a different amp and perhaps a very good one, but not a great one. And the Model 825 is a great amp -- in numerous ways, greater than any amp I've heard. It speaks not just in its own voice but in a voice I always wanted to hear, such is the pull, at least for me, of the utterly clear yet composed way it reveals all that's on each recording."
http://www.theaudiobeat.com/equipment/jeff_rowland_model_825.htmSaluti,
As for Marc's caveat that "class D almost never does it", I respectfully disagree with him... And suggest that listening to a broad range of current high performing class D amps tends to reveal that class D in general has the same chance of sounding great or horrid as any other topology.
Guido