Depending on your speaker and room needs, Denon for more neutral to analytical sounding speakers, and Pioneer for more rounded off, laid-back sounding speakers. So it depends.
Also, the Denon has the superior Audyssey MultEQ DSP circuit, which raises the sonic experiece to another level over other competing systems, all things equal. And, since most every single acoustically small domestic room needs EQ'ing of some sort, that is a deal maker for me! I'd go Denon. Good luck