Awesome! I have taken my daughter since she was little and now my little son(4) enjoys it too! For a family I reccomend the Japanese garden and the new My Big Backyard .
My daughter always and (still does) loved the Japanese garden. It is large and tranquil. The major attraction is feeding the fish! Feeding is not allowed in winter, but in spring and summer buy a bag of fish food for a dollar. Its enough to last a while for 2 or 3 kids. This is the ONLY food allowed! There are so many large carp, that one drop of food causes about 7 to jump up and fight for it. Little kids should use the red bridge which has handles, and older ones can use the wish bridge which is zigzag ( no handles or bars) and provides a closer view. My son enjoys this too.
My Big Backyard is a fun place geared toward the little ones. However my 12 year old daughter enjoyed the first look. There are small houses which focus on different senses like touch and sound. The clashing of cymbals can be heard from afar. Then the big treehouse has bridges, slides, and ropes. There are also mini exhibits like flower furniture and the floating bridge. Unlike a playground, it feels like a garden as well. Its beautiful with bright colors and funky designs. Leave the little ones on their own at the mini houses.
Usually there are free camps and classes for kids yearlong. My kids always loved them. We even joined the races and I attended a wedding there too!
But there is a lot for you to enjoy with your spouse or friends. Go to a quite garden ( there are many) and relax or take a hike on a quiet path. There are several benches scattered around. And if your bored waiting inside for someone, take the path opposite the main path to the Gardens. There are cool museum like exhibits and a nice window view.
No concessions are usually available, but ask the people up front if there is a vending machine if you hungry. I can't remember whre it is.