I didn't like chainsaw much because on certain mobs it'd ALWAYS try to go for the killing blow; and miss. It'd never do anything else. Same problem on bosses... I'd always run into a string of 4 or 5 attempts to "Leather Face" the boss before I'd get fed up with it. In the end, Edgar always turned out to be a healer for me anyways, mostly because of the noticeably large fail-scaling of his tools.