Just for discussion sake, the AV7705's THD+N is about 0.01%, which is NOT audible.
The 3dB down at 20 kHz is not audible either since most of us can't even hear beyond 18kHz. Also, a Frequency Response deviation of +/- 3.0dB is considered normal for SPEAKERS. So even if the AVP/AVP is ruler flat at 20kHz or 30kHz, your speakers will not be flat.
The question is NOT SOUND QUALITY. These components can all sound great.
The salient question is - Is the Marantz AVP with the THD+N of 0.01% and a -3dB at 20kHz LESS RELIABLE than the Denon and Marantz AVR's that measure better?