Quote Originally Posted by Kunkka View Post
berserk is more than a 40% damage increase (I'd say 45%ish based on my experience with inner beast heals). berserk is more than a 9% increase in damage. Berserk is better than fight or flight. Pacification is not 5 seconds of no dps if you are good.
1) Berserk gets worse as your gear increases, since it doesn't affect your Weapon Damage (as your weapon gets better, the boost you get from 'zerk becomes less, proportionally).
2) 20/90 = 22.2% uptime. Even if it increased your damage by 45% (which I'm almost positive it does not), that's a 10% overall increase, ignoring the pacification which will cost you at least some damage, even if cleansed.
3) FoF is a flat 9% increase over time, doesn't cost you any damage when it ends, and doesn't require a GCD from your healer.

Best-case, they're about equal, assuming your healer has free time. In most cases, FoF is just plain better.