I don't see how any of them can beat Kun, I have heard the claim that Bane and Vader had greater telekinetic power than Kun, but anyone who read Tales of the Jedi know full well that's a lie.
I would believe Vader to have better telekinetic power but Bane.
I will tell you something that Rhyltran told me.
Most likely, if a character in the movies uses an ability or lightsaber form in the movie, he is usually going to be the greatest user of the ability or one of the greatest.
But the character has to be in their prime when you are taking the statments. So Anakin Skywalker isn't gonna be the greatest master of Ataru even though he sequences from it in Ep. 2. But he was in his prime in Ep. 3 as Anakin and he used only Djem So.
Mace Windu: Vapaad
Sidious: Force Lightning
Obi-wan Kenobi: Soresu, Diplomacy
Anakin Skywalker: Djem So and mastery of Force Push
Darth Vader: Telekinetic Power
Kit Fisto: Shii-Cho
Sidious: Mastery of all Forms of Lightsaber and great telekinetic power.
And the list will go on and on.
of the time that statement is right.