Thanks A lot for your feedback. Also wanted to know if there is any benefit in having a better DAC chipset. Denon uses AK4458VN in their AVRs and Anthem AVM70 uses AK4490. Does this have any impact on sound?
I highly doubt you can hear a difference between -107 dB and -112 dB THD+N, unless everything in your audio chain is top notch including your loudspeakers, room, placement and your room has close to "0" dB ambient noise that is practically impossible.
For example, if the loudest spl you listen to is 70 dB average, 90 dB peak, -107 dB THD+N would mean all the noise and harmonics would be at -17 dB below 0 dB, worst case scenario. 0 dB is what experts consider inaudible to most people.
If you listen to ref level, that is 85 dB average, 105 dB peak, say even 115 dB peak, then -107 dB THD+N means the harmonics and noise that don't belong to the original music signal would be at 8 dB, so while that would theoretically be audible, it is still unlikely because your room noise would likely be at least 10 dB over the audio band so in addition to masking by the music itself, it also gets masked by your room noise.
All these assume you have super hearing.
Still, given the choice I would pay extra for the AK4490, it shouldn't be much more, may be $20, if that, and that's why I despite integrated amps because for AVRs I can understand because of the lower profit margin on per unit basis, but for integrated amps, there is no excuse for the likes of Hegel, Anthem, Yamaha, Parasound, NAD etc., to put second tier DAC ICs in their amps.
Keep in mind the DAC IC is just one part in the audio chain there are also other ICs such as the preamp volume control, switches (also ICs in most cases), and at least 1 or more opamp buffers. Each has its own THD and noise, so you do want each part to have the highest possible spec as distortions and noise of the parts all add up.
The DAC IC is not always the bottleneck, in the past, more often than not, the volume control is, because most AVRs and AVPs (including Anthem, NAD etc.) used LSI chips (large scale integrated) that to perform multiple functions and their THD+N specs would typically be worst than the medium scale ones that specialize in fewer functions. D+M upgraded that chip by using multiple MSI ones so if you buy their products from say 2016, the volume control chip should no longer be the bottleneck. They also upgraded the DAC IC tot he AK4458, the specs of it sort of matches the volume IC. Unfortunately they use the same IC in the AVR-X8500H and AV8805 and I think that's the reason why the X8500H did not measure that much better than the X3600H, or even the X3500H (at lower output). On the M side, it gets worse, I suspect (other engineer hobbyists too, I think..)HDAM is the one responsible for the added THD+N, but that's just my educated guess.
Those gents in that video you watch would not have said what they if they have viewed the bench measurements, read the information in the service manuals and have the knowledge to understand what they read. I bet they did not do any of such things, but simply read the marketing material and listened to the dealer reps.
