Darnell has such victim mentality and bullies all the girls in the house (he didn't do it to Nicole). He is sooo obssessed with what the outside are thinking - that man wants to win very much!!! He is a nasty, selfish piece of work
Yes, Rachel is not the most exciting - but, everyone generally likes to see justice done. By the time it gets to the final, it's not about how interesting people are or how much attention they demand - it's about plain and simple - what sort of person deserves to be rewarded in life? And I say Rachel for sure!!!