Relative to where he started, definitely Herc. Was a half assed "detective" that, even in a bureaucracy so full of incompetence, corruption and nepotism as the Bawlmore PD, he couldn't move up the ladder, not even to seargeant. No one who ever worked with him respected him or thought he was competent, and he was stuck doing the grunt work whenever he was detailed.
After a career full of failure, incompetence, corruption and abuse of power, during which he also found time to casually ruin Randy's entire life, he ended up in a cushy high paying job with a high powered law firm, has Levi as his mentor and gets to meet the family. And judging by his trajectory, he's probably going to end up being made a partner and become a millionaire.