Macbeth and Brutus, though both are guilty of regicide, have more differences than similarities. Macbeth is motivated by the prophecies of the witches and his own personal ambition. He essentially goes a on killing spree, becoming a cold tyrant willing to sacrifice anyone for his own pursuit of power. Brutus is motivated by doing what is best Rome, and tries his best to avoid looking like cold-hearted murders by not killing Antony (though this decision proves to be foolish and leads to his death).
Both tragic heroes are somewhat manipulated into their respective situations though, Brutus by Cassius and Macbeth by Lady Macbeth. Both also show signs of a guilty conscious by seeing ghosts of people they have murdered (Julius Caesar and Banquo), so they are similar in those ways.
As for Lady Macbeth, she prays to the gods to make her have the harshness of a man, and to take away her womanly emotions, in order to do what she believes her husband cannot do. In the beginning of the play, she is cold and harsh, and is described as more manly than feminine. However, as Macbeth gets more and more driven by power, Lady Macbeth succumbs more and more to her womanly emotions, eventually breaking under the guilt and emotional burden and taking her own life.