I used Expedia once to travel to Desire in 12/2009 and it worked great. Plus Expedia gave me a huge discount at the resort because I booked flights with them at the same time (Flights were no more money on Expedia than on the airlines website either btw). It was By far the least expensive of our Desire trips. I have heard that some people have had bad experiences with Expedia, but I also use them all the time for business travel as well and have never had a problem.
We book direct when using FFM's , because i see no reason not to. Its a simple system and I tend to think I may have more "Pull" if there is a problem on arrival. Not that that has ever happened.
We used Castaway travel on our first trip and it was "Okay" . Thats about all I can say for it. We never used them again because they employ Lomas travel for transfers and i was not impressed with them at all.
Our next trip is booked in May with Char travel and she has been fantastic thus far. I have been having some issues with the reservation and the dates but Char is working with me to help me modify as needed and provide advice as well. Never had that before !
Steve