It makes sense comparing Denon HEOS AVR vs Marantz SR7015 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 9.2 for Marantz SR7015. Regarding power, then HEOS AVR has such a W/Ohm ratio - 50/8, 65/6 when SR7015 has a power of 125/8, 165/6. The THD is the same and is 0.05%. Only the SR7015 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. Spotify can be used on each receiver. The HEOS AVR can work with the audio stream from Deezer, TIDAL, Pandora, Napster, SiriusXM, TuneIn Radio, iHeart Radio, Sound Cloud, and the SR7015 can receive a content from Deezer, TIDAL, Pandora, SiriusXM, Napster, SoundCloud. HDMI signal transmission in standby mode is implemented in each of the devices. The SR7015 can scale the input HDMI signal, unlike the HEOS AVR. Dolby Vision technology found support only on the SR7015.
The Denon HEOS AVR has 4/1 HDMI inputs/outputs versus 8/3 HDMI connectors of the Marantz SR7015. The HDMI Audio Return Channel (ARC) feature supports both devices. The HDMI eARC is available only on the SR7015. The Consumer Electronics Control (CEC) feature is present in most modern AV receivers and the models in our comparison are no exception. The HEOS AVR supports the protection of digital content of the standard HDCP 2.2, versus HDCP 2.3 in the SR7015. The SR7015 has a built-in phono stage for connecting a vinyl player. The HEOS AVR supports voice control via Amazon Alexa, Google Assistant, and the SR7015 - Amazon Alexa, Google Assistant, Siri, Josh.AI. An ECO mode is only available for the SR7015. The setup assistant will help you configure Marantz SR7015.
Only the SR7015 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the SR7015.