Jimmy was definitely the more ruthless gangster and Featherstone was pretty much legitimately insane and delusional at times. When he was in Nam he got drunk and his buddies had him circumcised and they said that made him lose it. PB is right, Coonan was the brains and real ruthlessness while Featherstone was the craziest guy in the neighborhood that people feared because he whacked a few guys in front of crowds. Mickey might have scared the shit out of HK, but don't think wiseguys from other parts of town were very intimidated by him.