ROTS | Sidious vs Windu Discussion

On topic:

Mace was able to match Sidious perfectly as a duelist while using his vaapad amp. However, this is only true if Palpatine was actually going all out in the duel to begin with, which, admittedly every thing points to the fact he was or very closely. Although, Sidious was still noticeably superior to Mace as a force wielder. 

The novel states that they were fighting at a perfect equilibrium. But this only applied to the saber combat, not including force powers. Sense they were fighting at a perfect impasse, there had to be some third party source to give a side an advantage. Mace gained the advantage by drawing off Anakin's fear which allowed him to disarm Sidious "legitimately".  

Sidious was still noticeably superior as a force user. Because once he used his lightning he overwhelmed Mace almost immediately and would of killed him if he had wanted.

Mace really has no answer for Sidious' force lightning. It's implied Sidious could won the fight with his lightning basically whenever he wanted too.

Palpatine toyed with the Jedi force that arrived in his office and could have used his superior speed or Force power to defeat Mace. Instead he chose to engage him in a lightsaber duel. This was a mistake on his part however as Vaapad allowed Mace to become his equal in lightsaber skill, and Anakin's Shatterpoint allowed Mace to genuinely disarm Palpatine.

At the same time though, Palpatine proved he could have ended the duel at any point with the Force - and he did. Mace disarming Palpatine is what lost him the duel, as he gave up the one thing allowing him to compete with Palpatine, and it cast him as the aggressor in Anakin's eyes. Palpatine merely had to play on Anakin's fear from there.