I've tried superpump250 and jack3d. The jack3d didn't really do much for me, but the SP250 def. did. I felt much stronger overall, mostly b/c I could push a bit harder. However, I have since switched to a more "natural" pre sup. Does SP250 have caffeine in it? Well, either way I started taking GNC rapid arginine 5000 before my work outs and the gnc post amino blend after, along with the amplified wheybolic. I also take 500mg of L carnitine in the morn, and 3g of L glutamine, as well. Not really wanting to try creatine b/c I don't want to hold all the water weight.