Very charming family-oriented movie with great animation! When I say family-oriented, I don't mean that it's just safe for kids to watch, but that at its heart is a theme of what it means to be a member of a family. The premise of the movie is that the extinction of dinosaurs didn't happen 65 million years ago, (the asteroid misses the earth), and we have an alternate reality where dinosaurs (Arlo's family, the T-Rex family he later meets) have advanced to the point of being able to talk and run farms (for the plant-eaters) and cattle ranches (the T-Rex's). Humans are not the dominant species, as pack animals similar to wolves, they live in families (the theme, again), are intelligent hunter-gatherers, and haven't developed speech yet.
If you don't get caught up in the paleobiology and such realities that Apatosaurs were extinct millions of years before T-Rex was around, and other logical flaws (remember, it's just a movie), it's very enjoyable and fun. In homage to earlier Disney flicks, they retained the stylistic form of the mid-century Disney dinosaurs (think of Dino in the Flintstones rather than the realism of the raptors in Jurrasic Park movies).
The writing is well done, with verbal humor that is surprisingly subtle for a kid's movie. I enjoyed scene after scene of just the dialogue. The human critter, Spot, has no dialogue, but his facial and body language are superbly done.
The bonus features are very interesting, and one part explains the fallacies in the movie, setting the record straight, as well as detailing the people involved in making the movie, and how the movie developed from their experiences on their research working with a real family who runs a ranch.
Though the dinosaurs are stylized and somewhat cartoonish, the animation of the environment is jaw-droppingly realistic. It's clearly based on Yellowstone or the Grand Tetons parks, trees' leaves and needles sway in the winds, the moving clouds throw shadows on the hillsides, the coloration of the river pebbles and the dinosaurs' skin textures are hyper-realistic, the water in the rivers and ponds realistically move and scatter the light. In some scenes, as the "camera" pans around, there are computer-generated artifacts of internal reflections of the sunlight on the camera "lenses" that just subtly pop in and out to make you think that a real camera was being used, when you know it wasn't, which shows how painstakingly the artists worked on this! It's a very clever trick that subconsciously works well.
If you have kids, then get this and watch it with them, you may find that you enjoy it more than they!