So I've just come back from shopping around and prices for both are pretty skewed. Firstly Lazada has the Denon as 2.9K which is way too much.
Street prices are around 2.2 - 2.4K. The more surprising thing is that the Marantz can be had for about 1.7K! The only difference I can see between the two is that the Denon has a slightly higher power rating of 125W vs the 110W for the Marantz, and the Denon has a slightly lower distortion of 0.06% THD vs 0.08% for the the Marantz. Perhaps more signifcantly the Denon supports Auro-3D but the Marantz doesn't.
But a $600 price difference for what are essentially the same AV receivers is a lot, unless Auro-3D is an important factor.
For me, I'm running power amps for L,R and C channels and only using the AV Receiver's amps for rears, surrounds and heights, in this case, the Marantz is the obvious choice.
Other minor differences I can see are that the Marantz has gold plated analog connectors and it also has surround inputs