A Breakdown of Islam

Islam is also an umbrella term, but the biggest sect of Islam is Sunni Islam, which makes up about 85–90% of Muslims. Shia Islam is the other sect, which makes up about 10–15% of Muslims. The biggest difference is the Shias believe only the family of the Prophet Mohammed should be leadership in Islam. Another much smaller sect is Ibadi Islam which is predominantly practiced in Oman. And Sufi Islam which is not its own sect as much as a mystical tradition with spiritual practices found in both Sunni and Shia branches.

It's important to note that like Protestantism, both Shia and Sunni Islam are themselves umbrellas for various schools of jurisprudence (interpretations of the law), called Fiqh, but unlike Protestantism, these different schools still pray in the same places of worship (Mosques). Mosques don't differentiate between the various jurisprudences as they all still follow the basic Five Pillars of Islam.

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It's also worth noting that there are strict groups in both of the major sects of Islam. In regions that are more multicultural than homogenous there tends to be fewer strict conservatives.