Does Elizabeth apply the same careful judgment to Wickham as she does to Darcy? Why or why not?

I don't think she does. She immediately starts trusting Wickham, believing him to be a respectful and decent young man, and she even believes his stories about Darcy, all of which turn out to be wrong. On the other hand, her judgment of Darcy is quite harsh, and it takes her a long time to change her mind about him and realize that in fact Darcy is the good guy, and Wickham quite the opposite.