the Bible - we believe it to be very corrupted by man over the years and do not take anything from it as proof. whereas, we believe the Qur'an to be free from any errors and we know that it has stayed the same since it was revealed over 1400 years ago. there is only 1 version of the Qur'an whereas there are many versions of the Bible.
That's interesting, this is my main issue with Christianity.