I would agree with JeffM above. It does work, but perhaps a little too well. I say that because, I've been trying to cut stimulants out of my diet as much as possible and I've consumed one of those little bottles early in the morning, and when it is time to go to sleep, I'm still wide awake, even without drinking any additional stimulants like coffee, tea, soda, etc. throughout the day.
No pros from me. It doesn't do a blessed thing for me. I'm better off with a cup of coffee. Cheaper, and it will perk me up for a while. It think it mostly works with the power of suggestion; you think it'll work, so it does.