It makes sense comparing Marantz SR7013 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 SR7013 has 9.2 versus 2.0 for Onkyo TX-8020. Regarding power, then SR7013 has such a W/Ohm ratio - 125/8, 165/6 when TX-8020 has a power of 90/6. The THD is 0.05% for the SR7013 but 0.03% for the TX-8020.
Characteristics of digital to analog converter (DAC) are different, 384 KHz/32-bit for SR7013 and 192 KHz/24-bit for the TX-8020. Only the SR7013 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 SR7013 has Bluetooth support. The Marantz SR7013 has support for AirPlay, AirPlay 2, and its competitor in our comparison - AirPlay. Only the SR7013 supports Spotify. Only the SR7013 provides HDMI signal transmission in standby mode. The SR7013 can scale the input HDMI signal, unlike the TX-8020. Dolby Vision technology found support only on the SR7013. Only the SR7013 supports HDMI Audio Return Channel (ARC). The HDMI eARC is available only on the SR7013. Of the two receivers in our comparison, HDMI CEC is present in only the SR7013. These compared receivers have a built-in phono stage for connecting a vinyl player. An ECO mode is only available for the SR7013. The setup assistant will help you configure Marantz SR7013.
Only the SR7013 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the SR7013.
The Marantz SR7013 is better receiver in this comparison. Check Marantz SR7013 price