I let me ears be the choice. I’ve head Denon’s and Marantz AVR’s latest was a 7010 I believe?
I understand why a lot of people hold the same opinion, or actually, believe that is the better way. Just that, well qualified and regarded experts, including Dr. Toole would tell you if you are to go with your ears then you do it blind, preferably double blind. It is very difficult for most of us to do a proper blind/double blind comparison obviously, so going with bench test results could be a good way to at least come up with the short list.
You have the D3 speakers that appear to have very good resolution and low distortions, so I thought they deserve preamp/prepro that also have very low distortions to begin with. It does not mean that the NAD's poorer THD+M, IMD, linearity would be a factor as it depends on other factors, but relatively speaking, based on very detailed measurements available on ASR, the Denon AVRs will more likely give you better results if in your applications the differences do translate into something audible. And I am only highlighting this as an viable option because they are so cheap relatively speaking, making it easier to upgrade even every 3/4 years.
Aside from specs, measurements and price, the NAD does look much better but it is just my subjective view. All else being equal I would take the NAD too because of its look.
I know it sounds a little ridiculous to use a 13 channel AVR as a preamp/pro, but the performance to price ratio is really tempting. The same can be said about the Yamaha CX-A5100/5200 too, but I would definitely wait for the CX-A5300 that I think have some significant improvements, including 8K for sure, and processing capability may increase from 11 to 13 channels.
Here are two very detailed technical reviews:
Denon AVR-X6700H AVR Review (Updated) | Audio Science Review (ASR) Forum
Review and Measurements of NAD M17 V2 Pre/Pro | Audio Science Review (ASR) Forum
Any of the Denon models in the top ten below performed better than the NAD. I linked the X6700H for you to read because you obvious have the budget and may prefer one that is made in Japan, just in case you would give the often despised AVR a try...