We have also booked with FD&D twice now. Have done it on our own, and through CAA also. Definitely wouldn't do CAA again; if you use an agent, make sure it's a Disney specialist. (Lots at CAA in particular say they are, but if you know more than they do, that's a bad sign...) Sometimes you can do stuff online directly if you've booked it with Disney, but Disney sure won't tell you if there's a way to get a deal, or if there's a new promotion that applies to your trip. 6 of one, half dozen of the other; if you're watching all the time and enjoy the "homework", do it yourself. If you have a GOOD agent you trust, there's less to remember. (I have to say, I like booking with FD&D partially b/c they are a Cdn company...the commission may not be much, but I'd rather it give it to another Cdn.)
Hope that helps, good luck planning!