What comparisons are being made between George Harris and Tom? How does George develop once he escapes?

George Harris looks white even though he has black lineage in him. This allows him more freedom when he escapes. George tells Eliza that he is a better man than the one whose "property" he is. He seeks freedom where as Tom has a pull towards a master, even if this master is less then kind. Once George escapes, he develops into a more enlightened self aware figure.