If you want magic ruined for you, take one of WDW's backstage tours and see what things look like behind the gates. Otherwise, as a member of the online disney community you probably know most of the stuff they were gonna tell you.
My parents went on it for their anniversary a little over a year ago, they loved it. They found out some things they didn't know, but also were told a lot of things they did know. They went kind of into the utilidor tunnels, not as far in as they wanted but they still got to see them. They went in special entrances on POTC and HM. They rode the train. And went and saw the Spectromagic floats. They ate lunch at the Harbor House. They loved it and we're going in December and I'm thinking of taking my sister on it on her 16th birthday since she'll finally be old enough to do it
I enjoyed it. If you're a hardcore fan most of the information won't be new to you, but seeing all the behind-the-scenes stuff was worthwhile. To get the most of it, try coming armed with some interesting questions.
The other tour I've done and enjoyed was Behind the Seeds at Epcot. It's shorter (about an hour) and cheaper, and is a nice alterative for those wanting a little bit of backstage magic without spending as much time or money as some of the bigger tours.