There are many instances of Pip being compared to the convict. Throughout the story, we see Pip squander the opportunities he has been so freely granted. He plays around learning to be a gentleman and enjoying himself. He thinks only of himself, and is ashamed of his roots. While he does attempt to learn to be a gentleman, he does so for his own gain and not in the interest of others. He assumes he is supposed to marry Estella.
Magwitch, on the other hand, always thinks of others besides himself. Although he got a bad rap and ended up in a difficult situation, he made the most of it. He was humble and hard-working, and never forgot Pip’s kindness to him. He gave everything he had to Pip and asked for nothing in return, except to see what became of Pip. That was his downfall of course.