i still have my h20 ... to me it is a sweetheart ... it is an older gen feed forward implementation (h360 gen1 ’sound engine’) and i agree this amp exhibits an ever so slightly leaner quality to its sound in the midbass, while still delivering excellent clarity, absolutely zero ss sizzle, and iron grip on the speakers...
interestingly, later, when they came out with the h390, they purposely tried to imbue a slight warmer hue to the sound with different parts selection in the pre stage, but achieved this at a slight loss of transparency, to my ear at least (i am speaking of using the 390 as an amp, not the digital section) -- this was not the case in the 590 which maintained its pristine clarity
my understanding is that with the h600 they are trying again to find that goldilocks yin vs yang middle ground
the current gen top rotels are very nice too, i have heard them in other systems, they are highly regarded, i have not been motivated to own one
i think one of the issues here that many systems contend with, as streaming becomes more common place, is that many mid-upper tier streamer/dac implementations still have a residual digital leanness glassiness harshness, and the top hegels as amps do not cover this fault up ... and i would go so far as to say that some dealers and their demo/show systems also fail to adequately contend with this

