TRIMAX Magazine has tested the Swiss Side GRAVON420 Wheels, and has posted a full review (in French).

Summary: 

• Set-up of the GRAVON420 wheels is quick and simple (<15 minutes).
• The wheels are a pleasure to ride: the stiffness of the wheels and the softness of the tyres compensate each other very well, making it a smooth ride. 
• Great grip is generated when riding with a low-pressured tyre. 
• Great quality of the hubs.
• The GRAVON420 is a great choice for both a race or a leisure ride.
• Classy look, along with great performance.

Conclusion: 

If you already own a gravel bike, a pair of GRAVON420 is the ideal upgrade to enhance the quality of your gravel riding!