Ground realities of the Sith of the reconstituted ancient Sith Empire
The Sith Order bestows a number of titles upon its followers, as befits their rank and power. These are the most common: Acolyte: A Sith acolyte has not yet completed his or her trials in the Sith Academy, and may well die before becoming truly "Sith." Sith: An acolyte who completes the trials and is accepted as the apprentice of a Sith Lord is considered Sith–no more, no less. Any non-Sith, however, is expected to refer to a Sith as "my lord" out of respect. Overseer: An instructor at the Sith Academy is called an overseer. Overseers are often Sith Lords, but that rank is not a requirement; they may simply be Sith with a talent for instruction. Sith Lord: A Sith who advances in the order’s hierarchy will eventually be elevated to Sith Lord. His or her name is preceded by "Lord" in formal address. In the modern Empire, "Dark Lord" is synonymous with this term. Darth: The strongest Sith Lords ascend to the position of Darth. Many take a new name at this point, symbolically embracing their transformation into something greater. Emperor: There has been only one Sith Emperor since the Great Hyperspace War over 1,300 years ago. He is supreme.
"There's no denying you are a master of the dark arts now. Only the most accomplished among us are named as lords among the Sith. You have more than earned the distinctions. I hereby confer the title of Sith Lord upon you. As lethal as you must be to become a lord, a Darth is the embodiment of death. Don't forget that."
Lords are more or less the equivalents to Jedi Knights, and Darth's Jedi Masters, but Freshest is more or less correct in the assertion that the Sith are more often than not stronger than the Jedi tend to be.
I'd agree that 'Sith Lord' is more the equivalent of 'Jedi Master,' and TOR Empire 'Darth' is more equal to famed masters or even Jedi council members. It's somewhat of an in-between rank that doesn't have a direct Jedi equivalent.
Eh, Masters *tend* to be more experienced and stronger than Knights, and a Knight who's a powerful warrior tends to be promoted.
Jedi do not base their ranks on power alone, they have ways to advance without power, but power is one way to advance- especially in times of war but not exclusively then (Ki-Adi Mundi got promoted for his skill as a warrior). And even those who get promoted for other reasons, 'deep insight in the force' or 'really good at training,' often leads back to power at least some.
For that matters, Sith can advance in ways other than direct power, like manipulation and ruthless use of knowledge and politics. If you have a network of contacts and assassins, you may end up advancing better than those stronger than you.
Becoming a Master does have more to do with becoming wise, calm, and able to control one's emotions than with power. But, a Jedi Master can't be a Jedi Master without being a powerful combatant, that's for sure. I think that's just a prerequisite. Jedi Master in terms of power is at the very least equal to the most powerful Knights. No less.
I'd take a Master over a Lord most of the time, but I'd take a regular Darth over a regular Master.