The thing about Rachel is, that if it wasn't for her being HOH and BB showing the others her VT which led to Rex bullying her, then we would probably hardly have seen her at all. In the beginning, she hardly ever featured on the Highlights Shows. She has just stayed in the background all the while.
I think her winning the HOH was the making of her. It certainly did her a lot of favours I think.
Sometimes she doesn't seem very intelligent, which seems strange seeing as she is training to be a teacher. She sometimes seems as though she is trying to be like Helen from BB2 or Jade from BB3.

Having followed BB quite closely, it is possible that she could be putting it on a bit, especially as she is an actress (her VT certainly showed that she can act).
She said that she is sometimes like she was in her VT. That I doubt - her boyfriend looked very quiet and she said he is quite shy. I just can't imagine him being with the girl in her VT, but I can imagine him being with the Rachel who is sitting on the fence.