The reasons are many.
I will mention the most important reasons: 1- One God: In Islam, there is only One God.
In many other religions, there are many gods.
What wil happen if the God decided something and His son decided another contradicting thing? There will be a conflict between them and the universe will be destroyed.
2-Simple and Clear Religion: You have to believe that there is no deity but Allah and that Mohammad is the apostle of Allah.
You have to worship the God.
And you will enter the Heaven.
Besides, Allah will bless your life in our world.
3-We believe that Moses and the Chirst are the apostles of Allah.
They have invited their followers to follow Mohammad -may the blessings and peace of Allah be upon him- when he appears.
But some of their followers have changed the Bible.
4-In Islam, there are harmony and balance between the soul and the body.
Islam does not forbid materialistic pleasures, but Islam is a unit of enjoying our lives and more important obeying our God and Creator.
5-Clear and Simple Answers to the following Questions: a-What is the origin of the universe? The God has created the universe.
b-What is the purpose of our life? We were created to live on the earth, but more important to worship our God.
c-What will happen to us after death? There will be the day after.
The believers will enter the Heaven and the unbelievers will enter the hell.