(Watchingthesky had quite the 'spiritual' experience reading the Koran)
That being said, I would not recommend anyone who is not strong in their Faith and walking with God read the koran. Seriously. There is a very strong, demonic spirit on those pages. A binding spirit, something bleak and dark.

I speak from experience. When I first started reading the koran, I wasn't exactly walking strong with the Lord. I was backslidden, to be honest. As I read through the book, I started having very strange and increasingly distressing dreams. There was a pull in it, something beckoning me to accept it, to give in to it, and most importantly to DENY CHRIST WAS GOD AND MY SAVIOR. I remember some of the most disturbing dreams -- I would be in arab garb and others would be demanding that I deny Christ to become "one of them". I always resisted, screaming at them that Jesus was Lord. I would wake up in cold sweats, terrified and exhausted.

It was truly disturbing and the one time in my life when I can honestly say that I was under spiritual attack for certain.

I started to feel like there was something in the apartment with me at times, watching me. Something dark, something that wasn't there for my benefit.

I started praying a lot after that, crawling back to Christ and things cleared up very quickly. Praise God!

Funny thing is, years later when I read through the Book of Mormon, I sensed the same kind of spirit, but it had nothing on me by that point. I saw it for what it was, I guess, and whatever spirits inhabited those texts couldn't get to me as I was walking much closer to the Lord.