It makes sense comparing Yamaha RX-V685BL 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, Yamaha RX-V685BL has 7.2 versus 2.0 for Onkyo TX-8020. Regarding power, then RX-V685BL has such a W/Ohm ratio - 90/8, 150/4 when TX-8020 has a power of 90/6. The THD is 0.06% for the RX-V685BL but 0.03% for the TX-8020.
Characteristics of digital to analog converter (DAC) are different, Burr-Brown 384 KHz/32-bit for RX-V685BL and 192 KHz/24-bit for the TX-8020. Only the RX-V685BL 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 RX-V685BL has Bluetooth support. The Apple Music service is implemented on considered devices: AirPlay. Competitors do not have built-in Spotify service. Only the RX-V685BL provides HDMI signal transmission in standby mode. The RX-V685BL can scale the input HDMI signal, unlike the TX-8020. Dolby Vision technology found support only on the RX-V685BL. Only the RX-V685BL supports HDMI Audio Return Channel (ARC). The HDMI eARC is available only on the RX-V685BL. Of the two receivers in our comparison, HDMI CEC is present in only the RX-V685BL. These compared receivers have a built-in phono stage for connecting a vinyl player. A voice control is not available. An ECO mode is only available for the RX-V685BL. The setup assistant will help you configure Yamaha RX-V685BL.
Only the RX-V685BL has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the RX-V685BL.
The Yamaha RX-V685BL is better receiver in this comparison. Check Yamaha RX-V685BL price