It is stated on the wiki as such:I'm going to have to strongly disagree that Kenobi equal's Vader at the height of Vader's power.
I was keen to say Kenobi exhibited force extension and usage of technique. I did not say Kenobi had the raw aptitude of Anakin. But Kenobi's mastery and skill of the force and saber are among the greatest of the Jedi Order- such that Kenobi has bested or equaled many Jedi, Sith and other warriors many times over. As is stated and shown numerous times w/r/t Kenobi, some of whom were among the most powerful of their era.He [Kenobi] later displayed his mastery of Force Push during his duel with Darth Vader on Mustafar, as neither of them were able to overpower the other while simultaneously using the ability.[12] The two struggled against each other for a short time, and though Kenobi was clearly giving ground, they both ended up being hurled in opposite directions across the room they were in. The fact that Vader's connection to the Force was, at the time, stronger than any known Force user in history further exemplifies Kenobi's mastery of the technique