Who is stronger - Exar Kun or Revan?
Exar Kun and Revan are both powerful Force users in the Star Wars Legends continuity. However, it is difficult to say definitively who is stronger, as they both have different abilities and strengths.

Exar Kun was a Dark Lord of the Sith who lived during the Old Republic era. He was known for his mastery of Sith magic, including the ability to create illusions and control the minds of others. He also possessed incredible lightsaber skills and was a skilled warrior.

Revan, on the other hand, was a Jedi Knight who later became a Sith Lord during the Jedi Civil War. He was known for his tactical genius and leadership abilities, as well as his proficiency in both lightsaber combat and Force abilities.

In terms of raw power, Exar Kun may have had an edge in his mastery of Sith magic. However, Revan's strategic mind and combat abilities may have given him an advantage in a one-on-one confrontation.

Ultimately, it is up to individual interpretation and there is no definitive answer to who is stronger between Exar Kun and Revan.
Could you give me your personal opinion?
In my humble opinion, Exar Kun is stronger. While Revan has a plethora of skills that may provide an advantage in a one-on-one fight, the power of Sith magic and the influence of politics in the Star Wars universe over encompasses Revan's physical advantages. Exar Kun, though incredible, required focus and time to channel his power. Given enough preparation he could easily be a threat to Vitiate, Darth Sidious, or Palpatine (Revan is known to have been defeated by Vitiate). Given an abrupt challenge with no preparation, Exar Kun's success would depend on his possession of the Sith gauntlet which provided him extra power, or imbuing his lightsaber with corruptive properties. Regardless, the power of Exar Kun cannot be denied.