I have used these (both transmitter and receivers) in the past with no issues whatsoever. No snake oil here! They do what they’re supposed to do, and they do it very well without any audibly noticeable loss and with a flawless uninterrupted wireless connection.
I’ve recommended these to others that did not want to have to run wires to their rear speakers and even to an adjacent room and building and they all have been happy also.
Do stay away from Bluetooth. With Bluetooth you will lose A LOT of fidelity.