Seriously- try Expedia when you get a quote from a TA. I am not speaking of anyone specifically but I know there are a lot of TA's on this site. Obviously they are going to see the "whole picture" and put a lot of weight in the other advantages a TA can offer... but for me I want the best price. I can easily see whether a cabin is ok by looking at the deck plan... I can also get my own air...
Expedia as I mentioned has really done a good job for me. They have done everything a local TA would have done IMHO. No worries with them- and I planned an entire trip to Scotland- all hotels and B&B's, transportation, airfare- not to mention two cruises totalling eleven passengers- plus countless other vacations over the years- so, all I am saying is: run it by Expedia (or Travelocity or that other one I now forget) before you buy.
Just my opinion!