EmperorSidious2
Master of Magic
If this becomes a mace vs Sidious fight, Mace isn't winning. Mace had many special circumstances that occurred that he won't be getting here. One of those being his boost. Vaapad I believe won't be as strong. My reasoning would be his personal anger. Yes it's still there, but possibly not as potent. He has already fought Sidious and redirected his power, and has Anakin on his side. He has achieved certain things that really reduce his inner anger.
Second. He can't use his shatterpoint like he did in the novel. Anakins on his side, or out of the competition due to Sidious' command of the force. With his Vaapad not being as potent anything less than what he brought to the table in ROTS is less than Sidious full power. With that he woudl be overwhelmed. Even if it is compleltely the same thy are still equals. With the equality, it will eventually come down to force powers.