[Darksheare]

They ARE competitors.
The SHI’AS believe their form of Islam is the only “called by Allah” form due to their view that the leadership of Islam went to Mohammeds son in law Ali upon Mohammeds death.
The rest of Islam had chosen Abu Bakr as caliph and leader of Islam.

[kabar]

The Koran is still the book on which Islam rests. They all believe that Mecca and Medina are the two holiest sites in Islam. Mohammed is still the Prophet. And they all go on the Haj to Mecca and Medina together. There are different sects in Islam like there are in any major religion whether it be Judaism, Christianity, Buddhism, Hinduism, etc.

We will just agree to disagree that they are competitors. I am not going to change your mind and you won't change mind.