I think I'd have to hand this to either Exar Kun or Marka Ragnos. Ragnos we don't know too much about, but common knowledge seems to dictate this, and for info on Kun, ask Lord Darkstar. He convinced me. And although I'm hesitant about this one, Revan after KOTOR amy stand a chance, but I'm not too sure, so I'll go with the first two.
this was done before
Originally posted by Darth Windu
Good point; but I'm sure they could have made something interesting about why he was one the most feared being in the galaxy for so long. Which would go into his rise to power so.....uhhhh.......whatever. 🙂
Ragnos decapitated lord simus i na duel when he rose to power, simus was another sith lord noone knows anything about.
In raw Force potential, Anakin/Darth Vader would be the most powerful. If he had reached his full potential, he would easily own the likes of Sidious, Revan, Exar, and Ragnos.
In terms of mastery of the Force, it all depends. Some excel where others do not. Kreia and Sidious were spectacularly gifted in Forsight. Sidious was also trained in battle meditation as well. Revan was well rounded in about everything - as was Exar.
But from speculation - Ragnos would probably be the strongest. Oh, and Tulak Horde is the greatest lightsaber duelist.