Reading through the Quran as I was finding the author sounded a lot more like the Old Testament prophets than Jesus or the apostles. So I asked some Muslims if they had shared a similar experience, after reading both the Bible and the Quran.
It prompted a very interesting discussion. My experience was echoed by some Muslims. One affirmed Paul contradicted the Quran and another said the Quran "is very similar in tone to the Old Testament prophetic books because instead of being narrations of events like the New Testament and Old Testament books like the Book of Kings, they are more like 'direct transmitted' revelations...like the book of Ezekiel, Isaiah, Jeremiah and so forth."
Many others, however, downplayed the differences between the New Testament, the Old Testament and the Quran, suggesting they reflected differences in context only, not actual content, because "all are revelation from same and only God." This did, however, leave me curious as to how they square the story of the woman caught in adultery and the story of the crucifixion of Jesus with the Quran, so I have much more to explore.
Overall though, it did affirm my impression that Islam is often closer to Judaism than it is to Christianity.