Devourer doesn't seem that OP as people say.
I've tried a few different devourer junglers: shyvana, aatrox, xin zhao, udyr, warwick, and master yi. All sated devourer does is pretty much this: it multiplies your dps by a slight bit depending on the itemization. And getting sated devourer isn't easy. In this game, dps doesn't mean everything. Going up to a champ, and landing those autos isn't easy. Still, I think it's pretty decent on some of them, like xin zhao and phoenix udyr, as it gives them a little bit of late game stat which they lack.
. You are a 40%CDR machine that will pretty much hit all 5 stacks of Black Cleaver on her basic Combo (Q+AA+E) plus her own passive (The proc from the devourer will cover the e extra needed for max black cleaver). So know you are hitting at 50% armor of your opponent and so are your teammates since is a debuff, tanks will melt... at the same time you are pretty tanky with 3k hp and around 200 armor and around 150 mr, full cdr means taht your shield and Q are up every 5 sec making you a cc machine and adding more tankyness... and you can even change 
and add even more damage without losing much armor....
becomes pretty much unkillable withouth a 
... 
will heal for flat 58hp plus 10% life steal and will steal do 8% damage of your current hp, now take into consideration that most Warwicks will run 
so you will be dealing reduced 20% damage to him....