But how does the SACD and DVD-A compare in sound quality to my Denon 5910 universal player with the analog audio output?
I don't know. Furthermore, anyone's answer to that question would only be speculation, and even then it's really entirely subjective. You could always just buy one when it becomes available in a few weeks and if you don't like it return it. You'd only be out shipping costs. Oppo offers 30-day satisfaction guarantee.