I think Atheists would win.
Many atheists I know research other religions as a topic of interest (even if only to 'prove' that said religion is false).
I know a lot about Judaism, Christianity, Hinduism and Islam. I know some things about some pagan religions and some things about Buddhism, too. I am not the only atheist with this knowledge. Several of my atheist friends have taken theology classes in college to expand their minds on the subject.