You know, those times when Harry is forced to admit he kind of likes the guy when he knows he is just bad news and he shouldn't?
I don't get the feeling he likes Marcone but he respects him. Given the creatures he deals with that he can't trust, Mab, Denarians, etc that means something to him but I don't think he likes him. He is still a 'scumbag mobster' to Harry, just one he respects.