From spoilers as well as things Ron Moore has said and hinted, the Final Five are "really different" cylons, and in a "All this has happened before and it will happen again" sort of way. I won't mention it here, but read the S4 spoiler thread if you dare about what the ancient name of the 13th colony that went to earth was. What "cylon" is and what "human" is goes a way back in time, I think.

So I don't think the Dylan Four are "evil". Tori (or is it Tory) may have committed a pretty evil act, but I do think it was entirely protecting themselves (and she wants the chief for herself, which is indeed a selfish act of evil like normal humans are wont to do anyway, but she had an excuse). I don't think the chief or even Tigh would've killed her. Well, Tigh just might have. Tory just took the bull by the horns. And she better pray the Chief never finds out (I'm sure he will later on, though )

-Richard