Having had an opportunity to test Denon HEOS AVR vs Pioneer VSX-933, I’d like to share my impression here to facilitate your choice of a new AV receiver.
The number of channels for receivers is different - 5.1 versus 7.2, respectively, for devices. In terms of power, there are differences, the HEOS AVR has such a ratio W/Ohm - 50/8, 65/6, while the VSX-933 has a power of 80/8, 165/6. The value of total harmonic distortion is also different, and for the HEOS AVR it is 0.05%, but for the VSX-933 it is 0.08%. The Bi-amping function is implemented only in the Pioneer VSX-933. Both Denon HEOS AVR and Pioneer VSX-933 can transmit an audio signal directly to the amplifier and bypasses any DSP processing. Each of the receivers has a Bluetooth connector. Access to the Spotify service is on each of the competitors. The number of available streaming services varies for receivers, the Denon HEOS AVR works with Deezer, TIDAL, Pandora, Napster, SiriusXM, TuneIn Radio, iHeart Radio, Sound Cloud, but the Pioneer VSX-933 works with Deezer, TIDAL, Pandora, TuneIn Radio. The quality of 4K/60Hz signal remains unchanged when transmitting from a source to a TV or projector via HDMI for both receivers. Signaling over HDMI in standby mode can provide the HEOS AVR and the VSX-933. Video scaling is only possible with the VSX-933. Operation with the Dolby Vision is only possible with the VSX-933.
The number of HDMI inputs/outputs varies depending on the receiver, the HEOS AVR has 4/1, and the VSX-933 has 6/1. HDMI Audio Return Channel is implemented in both devices. HDMI eARC is not supported by the HEOS AVR and the VSX-933. When comparing receivers, it becomes clear that each of the rivals can work with HDMI CEC. HEOS AVR and VSX-933 support the standard HDCP 2.2. In the presence of a built-in phono stage for connecting a vinyl player only at Pioneer VSX-933. For voice control in the HEOS AVR is used Amazon Alexa, Google Assistant, but in the VSX-933 is used Google Assistant. There is an ECO mode in neither AV receiver. The Pioneer VSX-933 can be properly configured using the setup assistant.
A Dolby Atmos multichannel audio format is available only in the VSX-933. Only in the VSX-933 realized a DTS:X surround technology.