My best guess would be the DACs' in the Denon would be better than those in the Adcom, but everything else in the adcom would be better than the Denon. If your using the Denon mainly for a pre-amp it may sound much better. I'm pleasently surprised as to how good my Onkyo 905 sounds using it for a pre!
What are your reasons for wanting to switch to the Denon?
What are your reasons for wanting to switch to the Denon?