Worth it is hard to say for someone else. I liked it fine, my mother loved it. It is very calm and has a Native American vibe to it. It is a nice slow down after a long day at the park, but it is really nothing like Fantasmic or Illuminations.
We are also going in June but have Tusker House reservations to get reserved seating at Rivers of Light. We are definitely going to see it since my mom loved it so much. She doesn't make many requests, and this was one of them.