While I have not booked at Disneyland, I always book my own trips. I am a control freak however and need to plan it all myself. Meant to add I have never found a price difference booking through anyone else.
There are no discounts available to TA's or online travel sites that you cannot get on your own. Therefore, it is most direct and easiest just to book through the Disney site directly.
I usually try the vacation packages offered on travel sites since it's so much easier to book it all at once than separately. I get confused easily when I book one thing here, one thing there, lol. I use Hotwire more than the ones you said though.
I personally don't like booking with these types of companies. I prefer to either do it myself or go through a good travel agent if I feel uncertain as to what I'm booking.
I usually try the vacation packages offered on travel sites since it's so much easier to book it all at once than separately. I get confused easily when I book one thing here, one thing there, lol. I use Hotwire more than the ones you said though.
I too book my own vacation. I book my vacation package thru Disney, my airfare through airline website (usually Delta) and my car rental through Alamo. Works for me.