I just wanted to comment that since I've been using 2 Spike before my harder workouts, I haven't had a workout where I didn't feel strong or have plenty of energy to get through it. Even one day when I was a little underfed and got really hungry during my workout, I still was able to finish it and not feel weak, which would have normally happened if I was hungry.
The boost that I get from Spike is definately different from ephedra, which I've cycled on and off for a couple of years now. No nervous feeling, just feel ready to go. And Spike works better for me than Power Drive, although I still use that on off days to aid recovery, since it's so reasonably priced.
Anyway, it works for me, and it's going to be a regular part of my supplementation from now on.