NO Shotgun is about the best pre workout supplement that I have tried...it combines NO with VPX Redline fat burn technology. It creates a good pump and drive for me to work out. I take NO Synthesize post work out as well. I have used Power Shock and I did like it but its not near what the combination of NO Shotgun and NO Synthesize is. I had a few rounds with NO Xplode and wasn't impressed. Wasn't impressed with Jack3d either...it takes 3 scoops of Jack3d to get where NO Shotgun gets me with one scoop. I always take the suggested one scoop of NO Shotgun and the effects never have felt decreased nor does my body get used to the product. If your doing crossfit or other cardio intense work outs I wouldn't recommend a pre work out supplement other then a fast acting whey protein.