It makes sense comparing Pioneer VSX-S520 vs Yamaha RX-V485 because they both are able to give some premium features.
Considered AV receivers have the same number of channels 5.1. Regarding power, then VSX-S520 has such a W/Ohm ratio - 50/4 when RX-V485 has a power of 80/8, 145/6. The THD is the same and is 0.09%.
Characteristics of digital to analog converter (DAC) are different, 192 KHz/24-bit for VSX-S520 and Burr-Brown 384 KHz/32-bit for the RX-V485. Only the RX-V485 supports Bi-amping feature. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing. Rivals from our review have Bluetooth support. The Pioneer VSX-S520 has support for AirPlay, and its competitor in our comparison - AirPlay, AirPlay 2. Spotify can be used on each receiver. The VSX-S520 can work with the audio stream from Deezer, TIDAL, TuneIn Radio, and the RX-V485 can receive a content from Deezer, TIDAL, Pandora, Napster, SiriusXM. Compared AV receivers retain the quality of 4K/60Hz signal when transmitting from a source to a TV or projector. HDMI signal transmission in standby mode is implemented in each of the devices. Both rivals can scale the resolution of the incoming HDMI signal. The HDR standard - Dolby Vision is supported by these receivers.
Each receiver has 4/1 HDMI inputs/outputs. The HDMI Audio Return Channel (ARC) feature supports both devices. The HDMI eARC is available only on the RX-V485. The Consumer Electronics Control (CEC) feature is present in most modern AV receivers and the models in our comparison are no exception. The VSX-S520 supports the protection of digital content of the standard HDCP 2.2, versus HDCP 2.3 in the RX-V485. The VSX-S520 has a built-in phono stage for connecting a vinyl player. An ECO mode is only available for the RX-V485. Both VSX-S520 and RX-V485 can be configured using the Setup assistant.
Only the VSX-S520 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the VSX-S520.