I have had a PowerFlarm Core for a year now and found it to be very helpful alerting me to gliders and other traffic. As others have already said, this alone justifies having one in your glider.

Another major benefit of having Flarm when flying with others with Flarm is that it really cuts down on the need for radio chatter as everyone can see where everyone is and how they are doing. Location and rate of climb/sink is displayed.