Alida:
Unlike the past where you could buy a park hopper ticket for just one day, currently The Park Hopper Option is an all-or-nothing add-on to your Magic Your Way base ticket. The option costs $54 plus tax and gives you the ability to visit as many theme parks during the day as you'd like for the duration of your ticket. Of course, the more days on your ticket, the better the value.
You mention the downside: if you have younger children, the transfer alone is tiring (not to mention time-consuming) and if you have a stroller and other child "paraphernalia," you might want to think twice. These are just two of the reasons I discourage parents of children from paying for the Park Hopper. My only exception when you have children is if you're visiting during a peak time of the year, like over a holiday, when you need the ability to "punt"--leave a park that is too crowded for another one, especially after Early Magic Hours.
Others on the panel feel differently than I do, but with four children, our family can find a lot of things more memorable to spend the money on to make our trip magical (like a dinner show, a trip to Goofy's Candy to buy edible souvenirs for their classmates back home, or even the
Pirates & Pals cruise).
Wishing y'all a magical vacation!
Whitney