One advantage to using a PVP is that they are Carnival experts and work with them all day, every day. A TA is usually booking all number of cruise lines, as well as hotels, airlines, resorts, etc.
Our PVP has been with Carnival for almost 20 years. If she doesn't know the answer to a question or is dealing with a difficult issue, she can get through to the proper people at Carnival without sitting on hold like an individual person or a TA has to. She knows us well enough that if she sees a deal she thinks we would like, she calls us.