I used to work at the Disney Reservations Center (DRC), where I trained phone agents and answered guest calls during period of high call volume. If you ask a DRC cast member, the answer would be something like:
"It's always a great time to visit Disney World. During busier times, park hours are extended and additional shows and attractions are added, letting you see even more."
Then, the Cast Member is supposed to turn the negative into a positive by saying something like:
"Being at Disney World during Spring Break also lets you experience the magic of Disney's Main Street Electrical Parade twice in one night!"
Technically, all of that is true. Since I no longer work for the Mouse, I'll tell you about the one topic that is purposely avoided when answering that question: dining. Extending theme park hours helps manage crowds. But, you can't extend lunch time or dinner time. Getting a non-quick serve table at a standard time gets much more difficult during crowded days. So, if you or your kids are used to a regimented meal schedule, you'll likely encounter problems.
As for the FastPass+ system, if you purchase your tickets in advance, you can reserve slots up to 30 days in advance. (Disney resort guests can do that 60 days in advance.)
If you are referring to the DoubleTree Suites Lake Buena Vista (at Downtown Disney), I stayed there earlier this year. Here is my review:
http://www.flyertalk.com/forum/hilto...l#post22514781
I also just stayed at the Hilton at Downtown Disney. (I checked out this morning.) It has declined significantly since my last stay. I'll write a formal review sometime in the next few days. But, the short version is that there were many minor issues that added up to an unimpressive stay. The DoubleTree was leagues better and no resort fee.