I've got Berserk glyphed on all toons, which adds 5 seconds to the effect.

It is usable in both Bear and Cat, breaks Fear and makes the toon immune to it.
The duration is 20 seconds.
Not sure on the refresh.

But will have Berserk vs one.
And Trinket vs another.
With diminishing returns on Fear.
And a long IWT range, to recover from a fear too.