Bossk was skilled, but he was far too emotional, letting his rage get the better of him. Whether he be "sharp" by Trandoshan standards or not, his rage proved to be a large flaw.
IG-88 didn't have the emotional problem, which made him, in some ways, more effective than Bossk. However, his AI assumed that Organics (Or Squishies as sometims call 'em) were inferior in comparison to him. So i a way, arrogance was IG-88's weak point.
D'Harhan was neat, but his tech was outdated, and he couldn't have survived for long in the Civil War era.
I'd have to say Durge is the next best Hunter, after the Fetts. I didn't like the character, as he was made for the old animated series (Which I despise) but I can't deny his skills. With his abilities, and track record of having kiled Mandos, Sith (Have to check on research for that one) and a couple Jedi, I think, he would easily fit into third place (or first, for this particular discussion).
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