I've been to the T-Rex here in Kansas quite a few times and if the one at Disney is similar (which I've heard it is), the atmosphere is amazing and the food is ok.
At the one here, there's huge fossil replicas outside and a moving dinosaur in a water feature that is catching fish. Inside, you are greeted by a life-size moving female T-Rex right as you go in that is protecting a nest of tiny hatching baby T-Rexes that also move. For seating they have a few different areas, most with either moving dinosaurs or another feature. One is a frozen area with moving mammoths, one is an underwater area with a big fish tank and giant jellyfish, one is a triceratops room, etc. Here, they have never had a problem with us taking a tour of the restaurant on our own and taking pictures with all the different dinosaurs.
My kids are small so we've never done the dino-dig. It looks like something that would be fun for the 5-12 year old age group. Similar to a giant sand box with dinosaur type bones in it. Not sure if you get to keep anything you find. I do know that here you have to pay extra to do it.
The Build-A-Dino store is really neat if you like Build-A-Bear. It has a variety of dinosaurs, including pink ones for any princesses in the family.
They have a "meteor shower" every half hour or so like Rainforest does with their thunderstorms. This can be intense for little guys if they aren't warned in advance. They flash the lights and there are big booms. In the frozen room you can see dinosaurs frozen in the ice only during the shower!
You will be paying for the experience. The food here rates about like an Applebee's or TGIFridays. They do have some cool drinks and desserts.
Hope that helps.