I guess it all depends. Is this your first trip? If so, then I'd say wait so that you can take it in without having to fight a bunch of people. If you do decide to go, just plan ahead, and you'll do just great.
It will be crazy crowded. Think the most crowded times at RnRC and ToT, but all over the parks. Great fun, but not a relaxing trip. You can still hit the major attractions with good planning, but not for WDW first timers who want to do it all!