Satele hasnt ever beaten any noteworthy sith (just dueled Darth Baras to a draw as a jedi master at best)
Tol Braga has dueled DC member Darth Sajar to a draw turning him to the light at best
Orgus Din lost to Darth Angral (who wasnt even on the DC)
Bela Kiwiiks lost to Lord Praven (Darth Angral's apprentice)
Wyelett beat Darth Baras but lost to his apprentice after he had become vastly more powerful from communing with the force.
Syo Bakarn hasnt beaten any noteworthy sith (albeit his other personality is about=to a DC member at best.)
Jun Seros the Jedi Battlemaster and Kellian Jarro lost to a bounty hunter.
Need i say more?
Satele Force pasted Malgus to a rock
Tol Braga...yeah, you are right
Orgus is aging, that's why he lost, plus he didn't go intending to fight
Bela Kiwiiks...well, we don't know much about her fighting skills, I'd bet she's a consular
Syo Bakarn, to be fair he hasn't even been seen in combat aside from his "other" personality
Jun Seros and Kellian Jarro lost to the best
bounty hunter in the galaxy