2piece bonus is incredible. It will be a pretty substantial dps increase. 4pc is hard to tell. But if you set your rotation up right, you'll be able to hit berserk and immediately do your innitial 5pt rip, then build up to a 5 savage roar, then probably get up to a ferocious bite and add 6 seconds or so. That's a pretty good bonus if played right. I'm just not a big fan of bonuses that effect cooldowns. I'd much rather some sort of passive increase or random buff.