For the most part, proc weapons are pretty cool. Some like the Bloodstained Zweihander (Z-spammer) proc fairly often, even if it's for relatively little damage. The cleric dark mace does some pretty good damage and refuels mana levels some.
The Emerald Broadsword (?) was a unique exception. It was still a cool weapon, but it had a lot of procs. One hit the mob with an emerald beam, another was an extra attack of sorts, another would randomly spell shield a member of the group, I think another healed the user a little bit and the last one burned your hand.
The only proc weapon that's truly dangerous are spec weapons. They chop limbs off mobs, dealing huge amounts of damage to mobs that are otherwise basically immortal. On the minus side, it's not uncommon to kill yourself or others of your group. Such is life
