I really love the [Hirudo] because of the actual free healing...
You go Grim Fury for the highest damage multipliers on your combos (increasing DPS overall).
If you're playing Volt/some other Warframe that boosts Attack Speed through animation speed-up, etc., just switch our Quickening.
If you can, run Arcane Fury for way more damage!
If you're using a Riven mod, replace whatever is on the mod with its corresponding stat.
-CC -> Sacrificial Steel (make sure it's a higher percentage)
-CD -> Gladiator Might
-The rest of the stats are self-explanatory
-If you want, your Riven could replace Quickening regardless.