I think you actually have more control of your vacation when you use MJ. Their agents are much easier to get in contact with then WDW Travel. They also apply discounts that become available as soon as they are published rather than having to call and see if WDW Travel will change it for you.

We have booked our last three trips with MJ (Terrisue) and could not be happier. Often our dates are up in the air until the last minute and she is very patient with us as we deal with our different scenarios.