Yes, I have explored other religions in as much depth as possible. Islam itself encourages gaining knowledge of other Faiths.
Islam as a religion has always acknowledged that there has been a chain of Prophets throughout history (Tradition mentions 124,000 such messengers of whom only a few are mentioned in the Qur'an). All these messengers have brought the same message albeit with differing emphasis and methodology depending on the society and the era. Since man is undergoing an evolutionary process the message has also been an evolutionary one, changing in certain characteristics while maintaining certain deep fundamental truths and realities that have not changed.
Because of this the Qur'an says that there has only been one religion (since there is only one source (God) and one Reality). The Qur'an refers to that religion as "islam" (with a small "i"). The same religion brought by 124,000 prophets throughout history. Although this religion has remained the same in its fundamentals (its metaphysical truths) it has undergone transformation in its external aspects (its laws, regulations, social structure, political structure etc.). Because of man's continually changing (evolving) condition, and because man has a tendency to alter things for his own self interest (resulting in corruption of the original message or its interpretation), new revelations were constantly needed.
So the position of previous religions in Islam's eyes is that they were, in their original form, islam. In many of them, corruptions have occurred over time, for many reasons, so that they do not necessarily any longer correctly represent their origins. The current manifestation of islam (called "Islam"), reasserts many principles of earlier forms of the same religion and at the same time acts as quality control over earlier revelations.
So, far from asserting its uniqueness over previous religions, Islam has identified all religions as differing (and evolutionary) manifestations of a single religion, "islam".