What are some big differences between the Qur'an and lets say KJV of the Holy Bible?

There are some similaarities. Both have a spiritual origin. One high and one low. Therefore both may contain elements of truth and startling revelation which give credibility. But when the qur'an comes along and declares that allah cannot beget, this is really quite remarkable and to a mature Christian mind quite obviously a direct attack on Christianity, for where would Christians be without The Only Begotten Son of God? Where in The Holy Bible do we find declarations of the things God CANNOT do? Nope, nope, Islaam disqualifies itself with this one rediculous error. An old Jewish tradition is: "From the mouth of two or more witnesses let every word be established. Mohammed has no second witness. The Gospel of Jesus Christ has 4. Matthew, Mark, Luke and John. I rest my case.