[Valin]

The Real face?
That's kind of a tough one to give a simple answer to.
Are you talking about Sunni , Shia, Sufi, Wahhabi...

A good place to start would be
The Encyclopaedia of the Orient
http://i-cias.com/e.o/index.htm

[Protagoras]

It's not tough at all. Either they believe in the Koran or they don't.

If they do, they are advocating and perhaps commiting murder and other evil things.

If they don't, they aren't really Muslims. It's simple.