With young kids, I love the park hopper option. Go to a park in the morning, come back to the resort mid-day for a nap/rest/swim, and when it's time to go back to a park in late-afternoon, we can go wherever we want, we aren't forced to go back to the park we were at earlier in the day.
Also, as the vacation winds down to a close, you can split your days between two parks, doing the "greatest hits" or just hitting the one or two rides/attractions you missed at one park before moving on and doing the same thing at another park.