I personally don't know 1st hand, but I walked a buddy through SFK the other day, then they returned the favor for my Warrior. His main was a 48 Warrior, and I was using my Fury warrior.
Well we had a bit of downtime, eating and bandaging, looting, waiting on the NPC to unlock the door, etc.
His Rage bar lasted 100x my rage. Not really, but it was slow enough of a decline to make me change Arms again :/
That's actually one of the reasons I'm thinking about keeping Arms.