I try to restrict my pre-workout usage to times when I am working long hours and wake up so tired and sore that I'm tempted to not even go to work, much less wander into the gym for squats. They get me hyped up and help with keeping my energy high throughout.
Side note 1: I haven't used a PWO for a month and my blood pressure is back down to 110/67 at resting, when taking a PWO is was up around 130/85.
Side note 2: I like K-Otic, but have to be sure to take in a LOT of extra water or I feel hung over after. Anyone else have this happen?