The tour was great. We entered the park around 8:30, so the beginning was very nice. The park was empty, it was interesting to walk around with no people around.
The tour is basically about the how and why of the Animal Kingdom. The tour guide tells you about the actual building of the park, and where some of the buildings and other artifacts came from. There is also the "back story", which is what the imagineers used as their storyline for building the park. For instance, the "fort" in Harambe was built to resemble a building that had been overrun by guerillas ( you know, the non-primate kind, I just had to say that ), and they took great pains to make the wood look like it had been burned and the building abandoned, right down to having "weeds" growing between the logs.
The highlight for me was meeting with the primate and gorilla keepers. They both came out and spoke with us for quite awhile about the care, and training of the primates. Very interesting.
I have never done the behind the scenes tour, so I can't help you with that one.
I think you'll enjoy it.