I remember reading an article about a study which suggested atheists generally tend to be more knowledgable about religions than "believers"
Not to say believers are ignorant, but when one already has chosen a set path or belief system as concrete, they are probably less likely to question or explore other avenues or doctrines, thus holding less knowledge of other belief systems.
Yes, I've prayed. Not sure I really believed it though. I was young, stupid, and desperate, and I figured, "why not?" My prayers went unanswered.