Anakin was one of the most powerful Jedi, and Darth Vader was one of the most powerful Sith. Anakin had greater ability to use the Force compared to Darth Vader, according to George Lucas. Darth Vader had nothing to lose, making him more dangerous.

Although Anakin Skywalker/Darth Vader are the same person, Star Wars audiences have long enjoyed debating who would win in a battle; however, both have unique skill sets that give them the advantage and flaws that make them vulnerable. One of the most impressive aspects of this character is that, as Anakin, he was one of Star Wars' most powerful Jedi, and, as Vader, he was one of Star Wars' most powerful Sith. Clearly, both versions of the character have significant raw power, but Anakin/Vader's complex history and character traits make this theoretical head-to-head fight more interesting.

In truth, Anakin/Vader wasn't in his prime...