Based on what? Resisting Vitiate's TP? :/ We know that the stronger in the Force you are the more difficult you are to TP per C'baoth's interactions with Luke and Mara in the Thrawn Trilogy. While nobody ever tried to TP Yoda or Sidious and they don't have TP resistance showings that wouldn't mean they're more susceptible to it. That's just common sense.
So if Vitiate's TP isn't going to affect Sidious then what else has he got? Lightning?
Sidious has already shown his to be superior. Revan knocked Vitiate's bolts aside while Sidious's lightning was powerful enough to rip Yoda's lightsaber out of his hands.
TK? Knocking DE Luke to the ground with a wave of his hand and matching Galen in a force lock is better then anything Vitiate's done in this department.
What's left? Esoteric powers? Sure, Vitiate is probably more knowledgeable in Sith Sorcery but are we going to assume he has an instant win ritual he can prep in 10 minutes to defeat Sidious with? I certainly won't.