Naturally, people into plants would enjoy the Gardens. What I didn't know was that this is also a great place to take toddlers. A friend brought us in with some guest passes that come with her family's membership, and we were happy we got a chance to check it out! My son enjoyed himself so much that we ended up joining also! There are rooms just for kids to play, with activities that rotate with the seasons. It's a great indoor option for the winter or a rainy day, and of course the outdoor areas like the Hershey Garden are great for nicer weather. There is also a daily butterfly release at 2pm where kids can hold a butterfly if they want to. The resident chameleon is also available to pet at certain times.
I would highly recommend the Glow exhibit in the winter. The displays of decorated trees, lights, and gingerbread houses are beautiful and festive. There's also a small train that kids can ride that loops around the lit displays outside.
Going twice in a year would make membership financially worthwhile, and membership also gets you entrance into Holden Arboretum!