It makes sense comparing Onkyo TX-SR343 vs Yamaha RX-A750 because they both are able to give some premium features.
A significant difference between the receivers in the number of channels, Onkyo TX-SR343 has 5.1 versus 7.2 for Yamaha RX-A750. Regarding power, then TX-SR343 has such a W/Ohm ratio - 100/6 when RX-A750 has a power of 90/6, 150/8, 150/4. The THD is 0.08% for the TX-SR343 but 0.06% for the RX-A750.
Characteristics of digital to analog converter (DAC) are different, TI Burr-Brown 192 KHz/24-bit for TX-SR343 and Burr-Brown 192 KHz/24-bit for the RX-A750. Only the RX-A750 supports Bi-amping feature. The Yamaha RX-A750 can transmit an audio signal directly to the amplifier and bypasses any DSP processing.
Only the Yamaha RX-A750 can connect to the Internet via WI-FI. Rivals from our review have Bluetooth support. Only the RX-A750 supports Spotify.
Only the Yamaha RX-A750 has support for High dynamic range (HDR). 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. The RX-A750 can scale the input HDMI signal, unlike the TX-SR343. The HDR standard - Dolby Vision is not supported by these receivers.
The Onkyo TX-SR343 has 4/1 HDMI inputs/outputs versus 6/1 HDMI connectors of the Yamaha RX-A750. The HDMI Audio Return Channel (ARC) feature supports both devices. Unfortunately, HDMI eARC is not available on monitored devices. The Consumer Electronics Control (CEC) feature is present in most modern AV receivers and the models in our comparison are no exception. Both models support the standard HDCP 2.2. Receivers do not 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-A750. The setup assistant will help you configure Yamaha RX-A750.
Only the RX-A750 has a Dolby Atmos multichannel audio format support. The receivers do not support the surround sound technology DTS:X.