Caffeine-Free Spike as a Study Aid?

Hey guys, I’ve used Power Drive in the past with excellent results for studying and for taking exams. I’m intrigued by Caffeine-Free Spike as it too boasts an intense focus effect.

Do any of you have any experience using Caffeine-Free Spike as a study aid or exam aid?

Can somebody lay out the difference between Power Drive and Caffeine-Free Spike?

Thanks.