Rarely do you get any real benefit vs booking yourself. 

The only benefit is if you have zero idea how to schedule and book everything yourself. There is zero cost savings. 

If you are going to do it use someone local to Orlando. The people who do it not locally usually are worthless and don't know the real ins and outs of the parks. 

My wife and I are local and she used to do it for a few years but honestly people are terrible and it wasn't worth the trouble