It makes sense comparing Marantz NR1504 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 NR1504 has 5.1 versus 2.0 for Onkyo TX-8020. Regarding power, then NR1504 has such a W/Ohm ratio - 50/8, 60/6 when TX-8020 has a power of 90/6. The THD is 0.08% for the NR1504 but 0.03% for the TX-8020.
Competitors' digital to analog converter (DAC) is identical to 192 KHz/24-bit. None of the models support Bi-amping. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing.
Both models do not have WI-FI support. Only the NR1504 has Bluetooth support. The Apple Music service is implemented on considered devices: AirPlay. Only the NR1504 supports Spotify.
HDR is not available on each model. Compared AV receivers are not able to transmit a 4K signal from the source to the TV or projector. Only the NR1504 provides HDMI signal transmission in standby mode. Both competitors are not able to scale the HDMI signal. The HDR standard - Dolby Vision is not supported by these receivers. Only the NR1504 supports HDMI Audio Return Channel (ARC). Unfortunately, HDMI eARC is not available on monitored devices. Of the two receivers in our comparison, HDMI CEC is present in only the NR1504. The TX-8020 has a built-in phono stage for connecting a vinyl player. A voice control is not available. An ECO mode is not present in each of the AV receivers. The setup assistant will help you configure Marantz NR1504.
None of the rivals equipped with Dolby Atmos multichannel audio decoder. The receivers do not support the surround sound technology DTS:X.