In my view, Lady Macbeth is far worse than Macbeth. Although they
both think of murdering King Duncan as soon as they hear the
witches' prophecies, Macbeth thinks more about what he may or may
not do, whereas Lady Macbeth immediately appeals to evil spirits
to give her the strength to kill Duncan.

When Macbeth first hears the prophecies, and when the first 2/3 of
it comes true, he does think of killing the king, but also,
towards the end of Act 1, Scene 3, he thinks that perhaps he
doesn't need to do anything to become the king : "If chance will
have me king, why, chance may crown me without my stir."

On the other hand, Lady Macbeth, on receiving the letter telling
her about the witches' prophecies, she immediately thinks that she
and Macbeth will have to kill king Duncan. She also decides that
Macbeth is too nice to kill the king, sayin that he "is too ful o'
the milk of human kindness" and when she hears the Duncan will
visit their castle that night, she immediately appeals to the evil
spirits, to (ironically) give her the strength to kill the king.
In Act 1, Scene 7, Macbeth is doubtfull of Lady Macbeth's plot to
kill the king. He doesn't think that he will be able to live with
the guilt of killing his king while he is staying under his very
roof, and then decides that he will not kill the king. This shows
that Macbeth is thinking about what he is going to do, and shows
that he does feel guilt and is weighing up the situation, unlike
Lady Macbeth who never thinks twice about killing the king.
When Lady Macbeth notices that Macbeth has left the room, she goes
to speak to him. Macbeth firmly tells her that they will not kill
the king : "we will proceed no further in this business". Lady
Macbeth, however, tells him that his love is worth nothing if he
refuses to go through with the plan, saying that his love is as
accountable as his indecisiveness. Macbeth wants his wife to love
him and wants her to trust him, so he agrees to go through with
their plan.

The way Macbeth questions and thinks about killing the king shows
that he knows that killing the king is wrong and that he will feel
guilty if he does so. On the other hand, Lady Macbeth never
questions or worries about killing the king. She never worries
that they will be caught and never worries that she will feel
guilty. Unlike Macbeth, she never weighs up what they are going to
do and instead jumps straight into it without thinking. This shows
that Lady Macbeth is far worse than Macbeth, because Macbeth
thinks about what he is doing, whereas Lady Macbeth jumps straight
into it, blinded by her own ambition.