Short review/what you should know:
Positive messages/role models: The toys trying to help the other one.
Violence/Scary scenes: Potential, especially for younger children. See spoilers at the bottom
Consumerism: None, as the toys in the film are not really those that this generation
Alcohol/Tobacco/Drugs: Smoking, the main villain smokes in most of his scenes.
You can think of this movie as a much darker stop-motion version of Toy Story, though not as remember-able. It can be useful to get older children; more specifically those over the age of 10; into darker animated movies such as many of Miyazaki's teenage movies like Princess Mononoke or potentially others such as Persepolis and otherwise.
Unlike Miyazaki's films or the majority of Pixar/Disney films, this film however is not really for children. There are creepy images, among them smoking and violence. Some of the younger children in the audience and some of the young adults seemed to be visibly creeped out by some of the scenes.
The movie is fine, I would give it a 3.5 stars if I could but it is closer to 3 than 4. It is too "cutesy" to appeal to older teenagers while it is too dark to appeal to young kids without scaring them quite a bit. The lessons are fine but they are taught in a way that does not appeal to many people.
Slight spoilers: In terms of violence, there are scenes of squishing, though it comes back together, as well as a toy leg melting which is rather creepy. In terms of scary scenes, those, and the kidnapping scenes/general peril scenes.