Right you are. I don't think KC enjoyed the actual process of murdering Caylee. She just wanted to get rid of her (for several reasons). Jodi is serial-killer-ish. She enjoyed thinking about the murder, the actual event, she wanted photos of it and relished/relishes reliving it.
Completely agreed Rose. For Casey killing Caylee was an ends to a means. I agree that with Jodi she seemed to derive pleasure in the actual killing. And since she has exhibited repeated stalker like behavior I believe that she would also kill again, if given the chance.