those guys do some good work, but they do put a heavy price on it, imo...i have used a.n. and it performed very well...but often find it hard to get or out of my price range for the whole system. have used a lot fo different nutrient companies, though lately i am not using anyone's hydro products.
my evolution has been, dirt, to hydro, to coco, to back to dirt...i probably will not grow hydro again...but a.n. works great, and i enjoy the email newsletter those guys send out..some good stuff to learn in those, imo.