Most nutrient is just diammonium phosphate and/or urea. Energizer would have some of that, plus magnesium, yeast ghosts, and various other things that yeast either need or just perform better with.
Fermaid K and Fermaid O are generally held as much better products, and I've never heard of someone not finding better results with either of these. I've definitely never heard of someone switching from either Fermaid mix back to those prepackaged nutrient mixes from the LHBS.
