Have been twice - would recommend it as a family outing. One tip - go in the winter/cooler months, and stay away during peak summer temps. Also, wear red (or other bright colors?) - red seemed to be a great draw to the butterflies, and several landed on me, but not others in our group wearing more muted colors.
Tickets are a little pricey - $42 for 2 adults (1.5 yr old was free). Amazingly, our 1.5 yr old sat through the movie perfectly, without wearing the 3D glasses. The atrium was super humid and a bit uncomfortable, but to be expected on a day where it was 115 out. During our first visit earlier this year, it was perfect temps inside the atrium - even with a (red!) sweater on.