I really liked Sheryl, from the little we saw of her. She seemed calm, sane, and kind-hearted. I can imagine her getting to the final, easily. Second to Stacey, is my bet.
She has the qualities needed to get to the end ... just gets on with it, and people like her. But most of all, she doesn't get too riled up by other people ... that's what will lead to the downfall of people like Jenny and Nigel, I reckon. (Sadly - cos I like them both)