I have a PVP that I've been working with for about 8 years. She's absolutely wonderful and when we booked our last cruise with a TA, I felt like I was cheating on her. The only reason I booked with the TA was because it was a group cruise.
We almost always book the Early Saver rate and had nothing but trouble with this via the TA. Now it could be that it was a large group and she was completely overwhelmed, but I really like having the control to do these things myself. Plus booking direct, I can see at any time exactly what I still owe, what my current price is, and what OBC I have (I usually have Shareholder and FCC credit at a minimum..and sometimes ES credits).
I'm not opposed to using a TA...I used to be one myself so I would love to support a good one...but since I have a wonderful PVP at Carnival I don't see the need to stray when I book Carnival. We are booked with a TA for our 2014 Princess cruise though!
Past Cruises -
Carnival - 20 cruises, 106 days (Platinum)
Royal Caribbean - 2 cruises, 10 days (Gold)
Norwegian - 2 cruises, 10 days (Bronze)
Disney - 2 cruises, 8 days (Silver)