I believe the Oppo could be comparable to the Denon, for about 1/3 the cost. I don't know if you are counting options such as region free, upconverting hacks and SACD.
The A2 is a different animal, a HD player that does upconverting will. If you want to enter the HD format competition, this may be the way to go. Plus I think it is cheaper then the Denon as well.
"Damn straight! Today the mad scientist can't get a doomsday device, tomorrow it's the mad grad student! Where will it end?!" - Professor Hubert Farnsworth