There are many facets to the Bible vs. Quran debate on the differences, as well as similarities, between the two. But the central debate between the Bible and the Quran is this: Does the Bible contain Tahrif (corruption) that the Quran corrects, or does the Quran attempt to corrupt God's words in the Bible?
The Quran was written about 550 years after the Bible and affirms the Bible as the word of God, less the alleged Tahrif. By contrast, the Bible refutes the Quran in its entirety with a stern warning in its final paragraph that nothing is to be added to or deleted from the Bible:
"...If anyone adds to these things, God will add to him the plagues that are written in this book; and if anyone takes away from the words of this book of prophecy, God shall take away his part from the Book of Life, from the holy city, and from the things that are written in this book." (Revelation 22:18-19)
God wrote the Bible using as His pens about 40 different people, most of whom did not know each other, over a period spanning some 1,600 years. Yet their works fit together with perfection, like a commercial airliner whose parts, produced all over the world, fit together with engineered perfection.
And since its completion in the first century AD, the Bible has been probed and scrutinized by each generation's scholars, both religious and secular, and withstood all of their challenges. In fact, more and more of the Bible's details have been and continue to be proven true as archaeology, astronomy, biochemistry, history, physics and other bodies of human knowledge advance (see Science & Bible).
By contrast, the Quran has not undergone such scrutiny, and this is as intended. While Christians welcome everyone to read, challenge and probe the Bible and its Author for themselves, Islam prohibits anyone from even questioning the Quran and its author.
In fact, Muslims are not even supposed to read the Quran in a language other than Arabic, so the vast majority of the Muslims in the world today, including the 220 million Muslims in Indonesia, the world's largest Muslim country, are kept from reading, let alone probing, the Quran for themselves.
Why does Islam try to limit access to and inquiry of the Quran and its author?
It is to hide the fact that even though it was dictated by just one man, the Quran is rife with self-contradictions, scientific, mathematical and other errors (see Errors in Qur'an).
Moreover, its author is a confessed false prophet - "I have fabricated things against Allah and have imputed to him words which he has not spoken." (Al Tabari, The History of Al-Tabari, vol. 6, p.111) - who even admitted to having mistaken the words of "Satan" (Ibn Ishaq, Sirat Rasul Allah, pp.165-166) as Allah's. See Muhammad False Prophet.