First of all, she is a complete idiot. No act. No one can act that well, and based on Dukes of Hazzard, we have evidence she can't act that well.
However, I wanted to clarify a comment the original poster made. Are you saying that Ashley is a more talented singer???? If so, I think you might have some hearing issues. Jessica is not headed for the Metropolitan Opera, but she actually has a pretty decent voice from a vocal perspective. The clips I've seen/heard of ehr singing that were live are not bad. Ashley, on the other hand, almost literally can't sing. She's right up there in lack of vocal skill with Britney.