I have seen some ads about 3 blades propeller. Worth it ? Does anyone have tried it ? They claim better performance, less noise and battery saving

Worth it ?
No

Does anyone have tried it ?
Lots have, but how many have continued using them?

They claim better performance, less noise and battery saving
If it was that simple, DJI's propulsion engineers would already supply them as standard equipment.
If they were so good, we'd all be using them.

Labroides Posted at 12-26 01:49
Worth it ?
No

Thanks Labroides, i have saved some money  :-)

Hello there Roberto Pirodda. Good day and thank you for reaching out. It would be best to use the original DJI propellers on your DJI Drones for reliability and compatibility purposes.  Just a reminder that DJI do not recommend you to use a 3rd party accessories specially 3rd party propellers on your DJI Drones. There is a  possibility that these propellers will work, however, since it's not tested by DJI we cannot guaranteed the reliability and the stability of the said accessory when in use and can void the warranty of your DJI Drone. Thank you.

The only advantage I could imagine is, if one broke the other two might better keep the drone in the air. But I doubt there is any evidence to prove it. Otherwise it is just more friction with the air.
In marine applications, the fewer the propellor blades, the faster the boat....except for low speed boats under heavy load. Then, the more the better up to about 5.