in what way do they love it?
Ive grown the same strain with and without it and there is noticeable difference in aroma and quality/quantity of the finished product. I have no idea whats in the stuff besides the micro nutrients it lists, amino acids, and what smells like molasses or something similar, but it is very similar to the other products listed in the thread. I have used it at full strength and notice no better results than 1/3 strength which is what i use. I bet you can mix a few less expensive products like an amino acid supplement, (botanicare vitamino is one), black strap molasses and a sulfer/mag supplement (probably not even needed if you are feeding enough sulf/mag) to make something similar, but as i said i have no idea in what proportions and there is probably other stuff in it.
As i said in previous post, the stuff is expensive and u dont need nearly 15ml/gal or feed it every feeding or feed it during veg. If i was growing on a larger scale i would likely find a substitute, but seeing as i use about 1/2 a bottle ($25) per cycle it is more convenient to just buy it.
I honestly am not sure why it works, but i have been told it feeds the beneficial microbes and helps them to stay alive when using chemical hydroponic fertilizers much the same as people use black strap for. This along with the amino acids give the plant an enhanced ability to uptake the nutrients and you end up with a more productive plant.