I've sold all those brands for about a decade and a half, and I have to completely disagree with Doggg. The Denon is anything but analytical, while at different price points, Marantz's sound has been somewhat of a mixed bag. If anything, the Yamaha's have been somewhat more analytical, by themselves. Older Marantz was thinner sounding at the lower/mid price points, but smoother near the top of their line.
The Yamaha's sound at anything bellow the Reference pieces have traditionally been a bit cool sounding, slightly recessed in the mid-range, a bit thinner in the bass, extended on top sounding. They did much much better usually being driven with better amplification (so did every other receiver, but the Yamie's really sounded better with outboard amps). The Flagships were better balanced.
However, I would want to know more about your system (speakers?), how you set it up, associated gear, room, acoustics, etc, before I recommend anything - because it depends.
However, without knowing your variables, the Denon will have a more warm full-bodied bottom end, good mid-range, overall musicality, and descent enough detail and top to be the most musically satisfying, as a stand-alone receiver, IMO. Basically, I think it will most approximate the NAD at that mid-level price point you're looking at, yes. I also think the Denon's will have bette dynamics than the Marantz from my experiences. I owned a couple Marantz pieces myself, a Denon or two, and some Yamies over the past 2 decades. Again, also sold/installed them professionally also.
Hope this helps