I do like Jessa's mean girl vibe, it's a nice change from keeping it sweet, i can't stand overly nice people, especially if they seem to be trying too hard/faking it.
And i don't think she's "mean" like the family hints at either. She's probably mean by compassion to her kool-aid chugging sisters. She seems more no nonsense to me, like a business woman. Then again, maybe she is a bitch, i don't know her welll enough to judge.