Kylo and Rey (Daisy Ridley) also blasted the Imperial Crusier open trying to Force pull the Lightsaber away from each other, so clearly, Kylo Ren is an extremely strong Force-wielder. Nonetheless, it can be said that Darth Vader is the more powerful master of the Force for one key reason: his temperament.
While Vader was certainly powerful with the Force, Kylo Ren is arguably even stronger, being able to freeze people in their tracks without even needing to focus on them. He can even read people's minds, which is another thing that Vader couldn't do. Even with being weaker with a sword, it's still possible Kylo Ren vs.
Kylo Ren spent 13 years training under Luke and a further 6-7 years under the tutelage of Snoke. He would undoubtedly be more competent than Luke during ESB. But Vader would more than likely still win with relative ease.
In Star Wars Legends and Canon, Galen Marek (Starkiller) is the only Jedi (other than Obi-Wan Kenobi) to put a beat down on Darth Vader/Anakin Skywalker.
As the grandson of Anakin Skywalker (on his mother's side), one of the most powerful Force users in the galaxy, Kylo Ren has the appropriate bloodline to destroy Palpatine. It was a redeemed Anakin Skywalker who killed Palpatine the first time, and the same midi-chlorians flow through Ren's veins.
He transforms the Galactic Republic into the Empire and declares himself Emperor, using Machiavellian manipulation to invoke martial law. Palpatine rules the galaxy for over two decades before Vader betrays and kills him to save his son, Luke Skywalker.
Even though Kylo Ren uses a red lightsaber, harnesses the dark side of the Force, and wears a cape, he is not a Sith. Because of that, he can never hold the title of Darth.
Vader, the only power who overrules him is papa Palpatine. The reason why Vader obeyed tarkin was out of a sense of respect for him as a military leader, not as his superior.
1 Darth Sidious
There has been no Sith, as powerful, meticulous, nor as evil as the Emperor himself, Darth Sidious. As previously mentioned, Sidious trained in the Dark Side by Darth Plagueis before Sidious killed Plagueis in his sleep, making Sidious a Sith Master.
We would have to give the victory to Darth Vader. While the two dark lords seem perfectly matched on their villainy and power, Darth Vader's lightsaber and ability to immediately use the force to choke Voldemort, without chanting any spell would end this showdown in seconds.
Aside from agility and telekinesis, Yoda could absorb and redirect Force attacks, like lightning. Because of his higher understanding, he would easily overcome Darth Vader in a fight, though that doesn't mean it wouldn't be a difficult battle.
Darth Vader defeats Darth Maul. The two Sith Lords engaged in a lightsaber duel, going through the volcano and onto a bridge situated over a river of lava, which collapsed, though they both survived and continued their battle.
Jedi Master Yoda is the most powerful of them all. This should come as no surprise, as he was the head of the Jedi Order in the prequels and was revered for his abilities during the original trilogy. Yoda's power is unmatched and was a real threat to Darth Vader and the Imperials.
Luke Skywalker is the hero of the original Star Wars trilogy, and he is also one of the most powerful Jedi in the canon. He has a natural affinity for the Force and is able to perform incredible feats with it, such as lifting an X-wing out of a swamp.
This might be a bit of a controversial pick at just number three, but Darth Vader, perhaps the best-known Dark Side user, is not the most powerful Sith ever. Born Anakin Skywalker, Vader became an extremely powerful Jedi Knight, one who was prophesized to be the "Chosen One" who would bring balance to the Force.
Darth Vader who wins? Vader not simply beats Rey, he destroys her. While the movies try to show that Rey is powerful, she's actually a mediocre force user without any impressive feats, except defeating Sidious, which was a special case since she was not actually fighting alone.
Darth Sidious, publicly known as Sheev Palpatine from Naboo, became the Dark Lord of The Sith after betraying and murdering his Sith Master Darth Plagueis. Sidious was the Dark Lord of the Sith during the last years of the Republic and the rise of the Galactic Empire.
Luke lost control of his anger, viciously attacking Vader, finally beating him down and chopping off his hand with his lightsaber. Despite slipping close to the dark side, Luke refused to surrender to the Emperor.
In the end, Thanos' neck is only as strong as his skin. Even if his lightsaber can't cut through Thanos' invulnerable skin, Darth Vader can still Force choke the Mad Titan and prevail.
Kylo Ren dies on Kef Bir (the ocean moon of Endor) shortly after Rey deals a mortal wound during a lightsaber duel on the wreckage of the second Death Star. Though Rey Force-heals him, saving his life physically, this blow, coupled with the memory of his mother and father, destroys the man known as “Kylo Ren” forever.
Kylo fears his master, he fears not being strong enough, he fears losing himself to the darkness, just as he fears losing himself to the light.
In the context of the story, Snoke is a "genetic strandcast" created by Emperor Palpatine to serve as his proxy in power. Snoke, whom Abrams called "a powerful figure on the dark side of the Force", was introduced as the leader of the First Order and master to the sequel trilogy's primary villain, Kylo Ren.