I didn't know that you had read the Koran so you would know enough to say that. While I have not read it, I do know someone who has and he tells me something very different. He tells me that the Koran is a comparatively stale read, that we should worship Allah basically just because. In contrast, the Bible shows man the nature of himself. We see stories that are thousands of years old, but are still just as true today as when they were written. We can point to them and say: "That's me!". My friend tells me the Koran doesn't read like that at all. The Bible matches "what is", making it unique.
Here, for example, the verses about Jesus (Isa)
This is a faint shadow of John 6, to give you a taste:
[5.110] When Allah will say: O Isa son of Marium! Remember My favor on you and on your mother, when I strengthened you I with the holy Spirit, you spoke to the people in the cradle and I when of old age, and when I taught you the Book and the wisdom and the Taurat and the Injeel; and when you determined out of clay a thing like the form of a bird by My permission, then you breathed into it and it became a bird by My permission, and you healed the blind and the leprous by My permission; and when you brought forth the dead by My permission; and when I withheld the children of Israel from you when you came to them with clear arguments, but those who disbelieved among them said: This is nothing but clear enchantment.
[5.111] And when I revealed to the disciples, saying, Believe in Me and My apostle, they said: We believe and bear witness that we submit (ourselves).
[5.112] When the disciples said: O Isa son of Marium! will your Lord consent to send down to us food from heaven? He said: Be careful of (your duty to) Allah if you are believers.
[5.113] They said: We desire that we should eat of it and that our hearts should be at rest, and that we may know that you have indeed spoken the truth to us and that we may be of the witnesses to it.
[5.114] Isa the son of Marium said: O Allah, our Lord! send i down to us food from heaven which should be to us an ever-recurring happiness, to the first of us and to the last of us, and a sign from Thee, and grant us means of subsistence, and Thou art the best of the Providers.
[5.115] Allah said: Surely I will send it down to you, but whoever shall disbelieve afterwards from among you, surely I will chastise him with a chastisement with which I will not chastise, anyone among the nations.
The Muslim I spoke to would compare the Koran favorably to the Holy Scripture, noticing that it is (we trust their Arab ear on this) highly poetic, speaks with a single dignified voice, and contains plenty of direct instruction to men, that is hard to misinterpret, such as
[5.6] O you who believe! when you rise up to prayer, wash your faces and your hands as far as the elbows, and wipe your heads and your feet to the ankles; and if you are under an obligation to perform a total ablution, then wash (yourselves) and if you are sick or on a journey, or one of you come from the privy, or you have touched the women, and you cannot find water, betake yourselves to pure earth and wipe your faces and your hands therewith, Allah does not desire to put on you any difficulty, but He wishes to purify you and that He may complete His favor on you, so that you may be grateful.
I didn't read it through. My statement simply reflects the fact that those who are Muslims hold that the Koran is a proof in itself that Islam is a "true" religion.
You see, faith requires no ordinary proof. Those who believe do not seek proof. That's why all faith is blind and irrational. The "reason" comes afterwords, and differs from individual to individual. We all have a story of our "own journey."