I do like that they add iron. There is not a single bottled formula on the market that does have enough iron, especially when people use the nutes at less than full strength.
The H3ad formula is good NPK wise. IMO it lacks Ca and micros though. So the biggest bump comes from iron...remember it is the thing you are deficient in that limits yield.
A whole lot of the variegation you see on certain plants is nothing more than an iron deficiency.
Hmm, that might partially explain why so many people have good results adding blackstrap molasses? It being an excellent source of Iron, and a good source of Calcium?