Oh, come on, ladies and gents. Azog was a warrior king who slew at least two presumably tough dwarves in the form of Nain and Thrór. He also showed a particularly inventive and nasty personality in the subsequent mutilation of the latter said corpse.
Grishnákh displayed the strength of his sword arm by killing... er... kidnapping two hobbits and, umm, getting killed by a spear in the back whilst skulking off.
++Azog
