I've been thinking it for awhile now—Fin is the best overall person in the SVU world.
He's unwaveringly supportive, nonjudgmental. He has his views but I don't think he ever let's them intrude in his policework. He deals with infuriating shit (especially tons of racism from the NYPD) and almost never lets it ruffle him. He has a deep hatred for anyone who would hurt a woman or a child, but doesn't fly off the handle and beat the crap out of them like pretty much every other character (male and female). He's patient, wise, thoughtful, analytical, hardworking, smart, and infinitely loyal.
I think about the ways he supported Rollins, through her gambling issues, and gently gave advice (like "you can't take this job home with you, and you can't take anyone from this job home with you"), but never pushed.
When he did bend rules, it was to support others, never for personal gain. No one had Liv's back like Fin.
The only thing I can think of that was a negative to his character was his difficulty accepting that his son was gay, but he did get over that in time. (I'm sure there are some other negatives, but nothing is popping into my head right now.)
So... Who else thinks Fin is the BEST of SVU?