I've recently started watching The Following of Fox. The antagonist, Joe Carroll, reminds me in many ways of Red John from The Mentalist. Both series feature a cult of serial killers. In the mentalist the Red John story is a subplot and backstory and character motivator, but each episode stands alone. In The Following the Joe Carroll story is the primary plot and each episode is directly related to Joe Carroll.
If the two had a battle of the serial killers, who would win? My money is on Red John.