SDM is a nearly perfect telling of a good story. No special effects or other devices. Just a compelling story told well with interesting and engaging cinematography.
American sensibilities will be stunned by the stark presentation of life in Indian cities. Our appreciation for a orderly society will be reinforced when faced with the randomness and incomprehensible random justice or the lack thereof in the Indian culture.
Throw in the completely confusing caste system and one has a cultural presentation that is beyond imagination. With no more than a few curse words and very few objectionable scenes the movie confronts the viewer with mob rule, rape, prostitution, drug and alcohol abuse, mafia organizations, child abuse, and more.
Go see it to stun your view of the world. Go see it because it has no major stars. Go see it because will make you cry.