I realize that my comparison involves two models that are a notch or so below both of yours, but here is my opinion for all it's worth.

I had a Denon 1910 for about a year and a half until it just decided to quit working. It was all the excuse I needed to buy an Oppo 970HD.
The difference in picture is night and day. The Oppo 970HD beats the pants off the Denon 1910. You asked for reference DVDs, well I was always disapointed with the picture in The Fifth Element (superbit edition) when seen in my Denon, particularly the opening scene in the piramid filmed in low light. The Oppo did a much better job there. Also any of the Lord of the Rings movies offer a good challenge for most DVD players.
I use HDMI/DVI to connect the Oppo 970HD directly to a Samsung 42" plasma.