The Emperor drilled pure hatred into Maul's mind over the years and the result is a dangerous and diabolical man. Maul is sheer evil and loathes the Jedi, however, he's a man that respects combat capabilities. If faced with a foe who can match his own extremely impressive level of skill, he would strive to give the challenger a swift death. When it comes to facing lesser opponents, however, Maul suffers from arrogance, and we all saw how well that served him in The Phantom Menace.