I use a travel agent that discounts the cruise. She is easy to work with and very quick to respond to e-mails, etc even on weekends. Rules don't allow me to list her contact information but others on the boards do use her. She was recommended to me several years ago by a person who was very active on the Princess boards.
The only drawback to using a TA is that all correspondence go through her. Princess will not talk to me, only the TA.