Audi A4 vs BMW 3 Series - Which one is more reliable?

I'm interested in hearing from fellow Audi enthusiasts on how our beloved A4 stacks up against its arch-nemesis, the BMW 3 Series, in terms of reliability. I've always been drawn to the sophistication and refinement of my A4, but I know some folks swear by the Bimmers. Who's got a take on this age-old debate?