It makes sense comparing Marantz AV8805 vs Onkyo TX-8020 because they both are able to give some premium features.
A significant difference between the receivers in the number of channels, Marantz AV8805 has 13.2 versus 2.0 for Onkyo TX-8020. The THD is 0.08% for the AV8805 but 0.03% for the TX-8020.
Characteristics of digital to analog converter (DAC) are different, AK4490 384 KHz/32-bit for AV8805 and 192 KHz/24-bit for the TX-8020. Only the AV8805 supports Bi-amping feature. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing.
Only the Marantz AV8805 can connect to the Internet via WI-FI. Only the AV8805 has Bluetooth support. The Marantz AV8805 has support for AirPlay, AirPlay 2, and its competitor in our comparison - AirPlay. Only the AV8805 supports Spotify.
Only the Marantz AV8805 has support for High dynamic range (HDR). Only the AV8805 provides HDMI signal transmission in standby mode. The AV8805 can scale the input HDMI signal, unlike the TX-8020. Dolby Vision technology found support only on the AV8805. Only the AV8805 supports HDMI Audio Return Channel (ARC). The HDMI eARC is available only on the AV8805. Of the two receivers in our comparison, HDMI CEC is present in only the AV8805. These compared receivers have a built-in phono stage for connecting a vinyl player. An ECO mode is only available for the AV8805. The setup assistant will help you configure Marantz AV8805.
Only the AV8805 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the AV8805.
The Marantz AV8805 is better receiver in this comparison. Check Marantz AV8805 price