The ones I tested that did not work are: Barbarian Patch: Gain an attack buff at the start of combat. Turtle Patch: Gain a defense buff at the start of combat. Mace Patch: +10% 1-Handed Weapon Damage Fencing Patch: +20% 1-Handed Weapon Damage Axe Patch: +10% 2-Handed Weapon Damage Katana Patch: +20% 2-Handed Weapon Damage The equipments that have equivalent buffs on them work fine though (Barbarian Armor, Gnome Gloves, Knight Armor...).
So, the main cons of this item is that it doesn't have any patch bonuses or armor, but being able to attack again everytime you kill something is pretty awesome for 90% of the game remaining after you first get it. It's not too hard to switch it out right before boss fights, but there's some boss fights where this item is still really useful. I strongly advise people to try it out.