I been gathering Revan feats now for the last year or two now, and it is now safe to say that I have personally went through every known source he is in.
Despite such, I still do forget details here and there, making my Respect Thread forever expanding. I recommend checking up on the thread every so often.
That being said, based of feats and accolades, Revan is exceedingly difficult to overcome in battle.
His lightsaber prowess is skilled enough to slaughter Sith armies, slay seemingly invincible Mandalores, and overcome Terentatek.
His Force prowess, ultimately, allows him to overcome "extraordinary" warriors with "tremendous" power of his own.
His Battle Precognition and military genius add to his already "immense power", making him seemingly unstoppable.
Very few can defeat him, which is why he is considered among the most powerful Jedi, Sith, and the Star Wars universe itself.
"There weren't many people able to face Revan across a battlefield and survive the encounter."
―Chris Avellone (KOTOR Designer)
As for the Exile, when I say this, I mean the one from KotOR II. Surik is obviously not on Revan level.
"Although Traya was more powerful, the Exile managed to defeat her in combat."―The Complete Star Wars Encyclopedia
The Star Wars The Old Republic: Revan novel then confirms that Revan was "greater then that of anyone else she had ever met, bringing forth the fact Revan is Darth Traya's superior.
There is also the fact that despite Darth Traya being corrupted by Malachor V's energies, Revan's power and will was great enough to resist where so many others failed.