Study the Preservation of the Quran

I have debated the preservation of the Quran with several Muslims, check out these articles (all in chronological order) for jam packed information:
 
http://www.answeringabraham.com/2012/01/quranic-preservation-errors-made-by.html
http://www.answeringabraham.com/2012/03/is-quran-perfectly-preserved-new.html
http://www.answeringabraham.com/2012/05/is-quran-perfectly-preserved-another.html
http://www.answeringabraham.com/2012/05/preservation-of-quran-continued.html
http://www.answeringabraham.com/2012/05/has-quran-been-perfectly-preserved.html (Includes the entire conversation with Bassam Zawadi)

I also recommend reading this book:

http://www.answering-islam.org/PQ/

And these articles: 

http://answering-islam.org/Quran/Text/index.html
http://www.answering-islam.org/authors/shamoun/quran_compilation.html

http://www.answering-islam.org/Shamoun/quran_variants.htm
http://answering-islam.org/Responses/Osama/zawadi_seventy.htm

http://www.answering-islam.org/authors/shamoun/rebuttals/zawadi/jesus_lord.html

http://answering-islam.org/Responses/Saifullah/bravo1.htm
http://answering-islam.org/Responses/Saifullah/bravo4.htm
http://answering-islam.org/Responses/Menj/bravo_r4bc.htm
http://answering-islam.org/Responses/Menj/bravo_r4bc_add.htm
http://answering-islam.org/Responses/Abualrub/allahs_identity.htm
http://www.answeringmuslims.com/2009/02/failure-of-muslim-response-to-ibn-masud.html
http://www.answeringmuslims.com/2008/12/aisha-and-ubayy-ibn-kab-on-100-verses.html
http://www.answeringmuslims.com/2008/12/islams-amazingly-unfalsifiable-claims.html
http://www.answeringmuslims.com/2009/01/quranically-confused-muhammads-chosen.html
http://www.answeringmuslims.com/2009/01/more-lost-surahs-of-perfectly-preserved.html
http://www.answeringmuslims.com/2009/01/fogg-is-lifted.html
http://www.answeringmuslims.com/2009/01/seven-ahruf-quranic-escape-clause.html
http://www.answeringmuslims.com/2009/01/manuscript-genocide-and-illusion-of.html
http://www.answeringmuslims.com/2009/01/quran-vs-bible-ex-muslims-comparison-of.html
http://www.answeringmuslims.com/2009/01/bible-quran-and-impact-of-textual.html
http://www.answeringmuslims.com/2009/01/bible-quran-and-impact-of-textual.html
http://www.answeringmuslims.com/2009/02/ibn-masud-on-zaids-mushaf.html
http://www.answeringmuslims.com/2009/02/quran-missing-prayer.html
http://www.answeringmuslims.com/2009/02/zaid-ibn-thabit-vs-ubayy-ibn-kab-on.html

http://www.answeringmuslims.com/2009/07/bassam-zawadi-vs-nabeel-qureshi-has.html

http://www.answeringmuslims.com/2009/04/another-quranic-deficiency-mentioned-in.html

http://www.answeringmuslims.com/2009/01/more-lost-surahs-of-perfectly-preserved.html

http://www.answeringmuslims.com/2012/05/quran-preservation-pamphlet-now.html

http://www.answeringmuslims.com/2008/12/islams-amazingly-unfalsifiable-claims.html

http://www.answeringmuslims.com/2010/01/abdullah-kunde-vs-samuel-green.html

We can only concur with the words of Mohammed Ibn Ishaq in conclussion:

Thus saith Muhammad ibn Ishaq [al-Nadim]: I have seen a number of Quranic manuscripts, which the transcribers recorded as manuscripts from Ibn Mas‘ud. NO TWO QUR'ANIC COPIES WERE IN AGREEMENT and most of them were on badly effaced parchment. (Abu'l-Faraj Muhammad ibn Ishaq Al-Nadim, The Fihrist - A 10th Century AD Survey of Islamic Culture, edited and translated by Bayard Dodge [Great Books of the Islamic World, Inc., Columbia University Press, 1970], p. 57)

According to this very same reference it wasn't just the MSS of Ibn Masud's Quran which were not in complete agreement:

Books Composed About Discrepancies of the [Qur'anic] Manuscripts. The Discrepancies between the Manuscripts of the people of al-Madina, al-Kufa, and al-Basrah, according to al-Kisai; book of Khalaf, Discrepancies of the manuscripts; Discrepancies of the People of al-Kufa, al-Basrah and Syria concerning the Manuscripts, by al-Farra'; Discrepancies between the Manuscripts, Abu Da'ud al-Sijistani; book of al-Mada'ini about the discrepancies between the manuscripts and the compiling of the Qur'an; Discrepancies between the Manuscripts of Syria, al-Hijaz, and al-Iraq, by Ibn Amir al-Yahsubi; book of Muhammad ibn 'Abd Al-Rahman al-Isbahani about discrepancies of the manuscripts. (Op., cit. p. 79)