Well actually, the review only mentions one area where the Yamaha might perhaps out perform the Denon, (given the definition of "arguably") and one area where the Denon definetly out performs the Yamaha, (albeit marginally)
Also "there is nothing of note" against the Denon whereas there is a negative comment against the Yamaha.
Thus, if the reviews are taken at face value the Denon is the superior product, (albeit marginally).
But then, it seems to be down to a coin toss. I wonder if What-Hi-Fi would be brave enough to give a joint award, (assuming of course that there isn't a contender out there that betters them both).