Calling the Qurân amazing is not something done only by Muslims, who have an appreciation for the book and who are pleased with it; it has been labeled amazing by non-Muslims as well. In fact, even people who hate Islam very much have still called it amazing.
Taken from the book 'The Purification of the Soul': This heart has only one concern: that all its actions, and its inner thoughts
and utterances, are obedient to Allah