Hitting at least 3 enemies with an attack, increases your cleave by 140-200% for 2 seconds.
2.5-4% Bonus Critical Chance on Chained Hit. Stacks 5 times.
14-20 Critical Chance on Weak Spot Hit until your next Critical Hit. Stacks 5 times.
70-100% Critical Weak Spot Damage.
Equally effective with a chainsword.
Less effective with an eviscerator or heavy sword.
Alternate guns are: Braced Auto, Shredder Autopistol, Boltgun, Kant Shotty
Running DMG buff instead of Damage Resistance on Chorus is a valid alternative too. I personally think Damage Resistance is synergistic with Chorus and prefer it because of that, but there is a valid argument in saying that it ends up being too much Damage Resistance in the condensed 10s time frame.
If the damage buff applied at the first pulse instead of at the end, I'd instantly grab it instead of Damage Resistance.