Obviously I like Vanessa more. Except her reaction on Rachel last leg, Vanessa is always funny and interesting to watch. Besides I hate Rachel overreacted most of the time, she's so conscious that the camera is in front of her so she made a lot of drama of it. The unnecessary whining and crying (e.g. can't get taxi after RB in leg 2) really got on my nerve...
PS. I also think Vanessa/Ralph intro is hilarious as well!!