If you like Magical Girl, especially the Magical Heroine ones, that would be the classical story. However If you still under 13, you have to watch it later.
Puella Magi's storytelling would like Watchmen: dark, cruel social problem background, with the humanity struggles (including the faith, in Kyoko's Christian case)... But less bloody violance and sexual stuff, and same with the ending of Faust, good ending with hope. It is let more teenager can reach the story, and rethink themselves.
Kaname Madoka, from shy to brave changing, having strong power with kindness heart, and her legacy life, is it a tribute to Optimus Prime? Maybe.