It makes sense comparing Denon HEOS AVR 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, Denon HEOS AVR has 5.1 versus 2.0 for Onkyo TX-8020. Regarding power, then HEOS AVR has such a W/Ohm ratio - 50/8, 65/6 when TX-8020 has a power of 90/6. The THD is 0.05% for the HEOS AVR but 0.03% for the TX-8020. 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. None of the competitors supports Auto speaker calibration.
Only the Denon HEOS AVR can connect to the Internet via WI-FI. Only the HEOS AVR has Bluetooth support. Only the HEOS AVR supports Spotify.
HDR is not available on each model. Only the HEOS AVR 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 HEOS AVR 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 HEOS AVR. The TX-8020 has a built-in phono stage for connecting a vinyl player. An ECO mode is not present in each of the AV receivers. Unfortunately, the setup assistant is not available in each of the models.
None of the rivals equipped with Dolby Atmos multichannel audio decoder. The receivers do not support the surround sound technology DTS:X.