I was working on this reply (saved it as a draft) before any others were posted. My experience is different.
You can lead a Christian to a library, but you can't make him read.
Great line

Is this also the case in Islam, or am I under the wrong impression in assuming that most practicing Muslims at least know their scriptures and their various interpretations and, therefore, can claim a more solid basis in personal knowledge for their beliefs?
In my experience, Islam is a knowledge based religion, like Orthodox Judaism. One has to read the books to be able to practice. Of course there are those that don't (many now), and just follow along with what everyone else is doing. But to me, Islam doesn't have as many glaring contradictions as Christianity does (if one accepts the possibilty of miracles), Muhammad and friends tied everything up nicely. If something from the Qur'an differs from the Bible or other Jewish books, the Qur'an is correct and those books have been corrupted. If there seems to be a contradiction in the Qur'an, it is not a contradiction, an explanation can be found, or one side has been abrogated and the other is the truth. If something seems off in a hadith, it is considered weak or fabricated. And on and on...