How does when does Huck compliment and Denigrate Jim?

Huck frequently uses his schooling to make Jim feel inadequate. Huck plays practical jokes on Jim that are rather humiliating. At the same time Huck compliments Jim on his devotion to family. In Chapter 42 Huck explains that Jim is a good "Nigger."

“I never see a nigger that was a better nuss or faithfuller, and yet he was resking his freedom to do it…He ain’t no bad nigger, gentlemen; that’s what I think about him.”