Actually this topic I opened for giving views on the issue. But in your messages I see problems.
First, your rhetoric exhibits an "our religion is older" behaviour. I have regard for verses of the OT and NT that are not in contrast with Qur'an. So, do not get tired by citing verses from the Bible. Let's speak about concepts, contrasts, similarities etc, but not use verses as evidence, because they are not acting to that effect. No verse in the Bible can make me disbelieve my religion. And vice versa. It is that simple!
One cannot evaluate religions from only theological point of view. Religion also has psychological, social, economic.....dimensions. So when I look at west I don't see a Christian world. How many Christians uphold the principles, and observant. From this pov Christianity today is a weak and unsuccessful religion. I read much on how churches helplessly strive to attract adherents. Actually only this is enough evidence for it not being the true religion of God.
Mormonism and Jehovah's Witnesses is not comparable to Islam. These came within your religion and are also evidences that Christianity is decaying away. These cults are not our problem, they are yours! 8)
On the other hand Islam is a powerful religion with its theology, spiritual inspiration, social order etc. It is a complete way of life. It is gaining strength although muslims do not exhibit a good role model. Because Islam itself, as the true religion of Allah, has an appeal. Qur'an is the ultimate word of God. Read it with sincerity and open your heart to what it inspires.