This is an anime site, not a Star Wars site
Go to comicvine for feats
Not really a battle thread, but I'll bite.
- at the time of revenge of the sith was equal to Yoda, perhaps even slightly stronger (debatable)
- at his prime (in his new body) was capable of creating wormholes when enraged and could enslave the minds of millions in order to fuel his power. Was also a skilled enough combatant to defeat Luke in a duel (and this was some time after return of the jedi).
- could kill jedi and jedi-level enemies pretty much instantly with his force lightning
- mastered every sith technique.
- hailed as the strongest jedi of the age
- defeated a dark lord of the sith (malak) even after the latter had been amped by more force users
- mastery of both the light and dark side of the force
- was capable of putting up a fight against Lord Vitiate (who some believe to be the most OP star wars character of all time).
- at his best was capable of defeating Sidious in lightsaber combat
- when meditating could track spacecrafts moving at lightspeed
- could use the electric judgement technique, which is basically a one-hit kill version of force lightning
- mastered telepathic abilities to the extent that he could cut off Sidious.
Here are a few more of the best force users.
- before his prime was able to bring a whole temple down with the force
- capable of facing multiple jedi masters and defeating them
- with orbalisk armour was even stronger and practically unbeatable in single lightsaber combat (the best combatant in the jedi order at the time couldn't do a thing on her own).
- could kill people just by speaking
- was able to keep his body together after it had degraded just through the force
- consumed the life force of entire planets to fuel his hunger
- he alone was stated to be a threat to the entire galaxy, to all jedi and sith alike.
Lord Vitiate/The Sith Emperor:
- he defeated Revan at his best without much trouble
- complete mastery of the dark side
- was defeating sith lords and conquering planets at the age of 14
- was able to beat most enemies simply by crushing their will and making them his pawns
- deceived dozens of sith lords and then added their power to his own, becoming even stronger.