Uthar was a charasmatic Sith, but still a pretty typical Sith with his "If I must explain it, you don't belong here" vibe. Yuthura did more to explain the Sith in six minutes than Lucas did in six movies (MAJOR Kudos to Drew & David at Bioware for cooking her up!). She explained the ideas and the Sith philosophy in a logical, thoughtful manner that gave structure behind the apparent cackling madness, and made it seem almost a damn shame that the Sith and the Jedi had to constantly kill one another.
And when you befriend her, and she walks away in the end? Since I play Korriban AFTER the big reveal, I see it as a fitting touch. You didn't just save her. You saved yourself.