Hero of Tython wins this although it will be a tough fight. No question that Jaina is REALLY good but look at some of the Hero's victories;
* Darth Angral, who was noted as Dark Council material.
* Sadic who was not only a powerful Sith but went through the Power Guard process. Even standard Power Guards were noted as strong enough to be threats to Jedi/Sith.
* The Imperial Guard, whom even the Dark Council were scared of.
* Scourge, who had spent over hundreds of years killing top level Sith.
* The Emperor. People seem to forget that even though he wasn't at full strength he was still heckuva powerful. This is the guy who destroyed his Sith Lord father's mind when he was a nine year old.
Jaina will give a good match but ultimately the Hero prevails.