What are the differences in creed between Ahl al-Sunnah and the Shi'a?

The Shi'a are many factions, some of whom are infidels who worship Ali, Fatima, and Hussein. Among them are those who claim that Jibreel (Gabriel) betrayed the trust and that prophethood was meant for Ali. And among them are the Twelver Imamiyyah who say that their Imams are superior to angels and prophets. There are also those who prefer Ali over Abu Bakr, Umar, and Uthman; he is mistaken for going against the consensus of the Companions, but he is not an infidel. The Twelver Imamiyyah and the Nusayriyyah are among their most wicked factions, and they are called Rawafid (Rejecters) for rejecting Zayd ibn Ali. A Muslim is one who worships Allah alone, believes His Messenger, and follows what he brought. So whoever claims Islam yet worships other than Allah, or insults the religion, or abandons prayer, or mocks the religion or its rituals, or disbelieves Muhammad (peace be upon him), or claims that the message was not completed, then he is not a Muslim.